Talk:Physics of glass

Textbook

There is still one thing you need to think in (copied from WP:NOTTEXTBOOK): "Wikipedia is an encyclopedic reference, not a textbook. The purpose of Wikipedia is to present facts, not to teach subject matter. It is not appropriate to create or edit articles that read as textbooks, with leading questions and systematic problem solutions as examples. These belong on our sister projects Wikibooks and Wikisource. Other kinds of examples, specifically those intended to inform rather than to instruct, may be appropriate for inclusion in a Wikipedia article." - If you do not consider this, an editor might place the {{textbook}} template on the top of the article. Good luck... --Afluegel (talk) 22:27, 17 March 2009 (UTC)

I'm tempted to do that right now but will resist in the hope that the issue gets fixed soon. Jdrewitt (talk) 18:49, 18 March 2009 (UTC)

It might be good to wait until the template {{underconstruction}} disappears. But even if the textbook character does not change as fast as would be ideal, this is just a shortcoming as many other articles have as well, i.e., it is not a reason for immediate deletion of major parts. The topic is still important for the topic glass. After some months or years the article will certainly have changed significantly through the input of other editors.--Afluegel (talk) 20:54, 18 March 2009 (UTC)

Important References

Some very fundamental texts that deal with the Physics of Glass. The work of Austen Angell A massively cited author should also be read. (Just check out his Publications cited more than 100x --> WOW

1. Zallen, The Physics of Amorphous Solids, John Wiley, New York, (1983) google books link
2. Cusack The physics of structurally disordered matter: an introduction, Adam Hilger in association with the University of Sussex press (1987) Amazon link
3. Elliot, Physics of amorphous materials, Longman group ltd (1984) Amazon link

I think it is very important to include these references and would like the construction template remain on this article until such a time that these and other more up to date and fundamental references on the physics of glass have been considered incorporated. Jdrewitt (talk) 18:49, 18 March 2009 (UTC) (still on a wikibreak but obviously can't stay away!)

Excellent suggestions !!!

Dr. Angell (see Ref. 4) is one of the truly great research scientists of our time. I met him at a conference of the American Ceramic Society (East Coast Division) once when I was much younger, and enjoyed showing him some of my work on Colloidal crystals at that time. We discussed the nature of the glass transition in disordered colloidal systems (Colloidal glasses) over gin and tonics ;-) -- logger9 (talk) 23:56, 18 March 2009 (UTC)

I wanted to thank you for helping me out with some of the titles of the journal articles. I have been trying to find the time to take care of that myself. At one point in time, I had them all neatly stacked and categorized in a closet. But that was many, many moons ago.

The most satisfying thing is to see them being given new life :-) -- logger9 (talk) 07:55, 20 March 2009 (UTC)

Tendency toward crystallization ?

While statistically and or mathematically, there is a driving force toward crystallization, there is no physical mechanism or evidence that all glasses "tend towards" the crystalline state, not even on a "geological" time scale.

Many glasses, for example, traditional silicate glasses more than a few degrees below their glass transition temperature, show no evidence of crystallization. Five degrees below Tg (Kurkjian's work) it takes over a year at high stress to see any evidence of relaxation of the stress in the glass, let alone the amount of rearrangement necessary for actual crystallization to occur. This is at energies near that required for the liquid state to form. At hundreds of degrees below this, the rate of atomic rearrangement towards the so-called inevitable mathematically stable crystalline state would be so low as to laugh at the age of the universe, let alone geological time scales. —Preceding unsigned comment added by Njsustain (talk • contribs) 00:23, 19 March 2009 (UTC)

Most arguments to the contrary are largely academic -- and highly respected within the scientific community. Some empirical proof I can currently see in the literature is that relating to recent work on quasi-elastic (inelastic) light scattering in glasses.

On the Origin of Quasi-Elastic Light Scattering in Glasses, Europhys. Lett., Vol. 57, p.838 (2002)

Very Low Frequency Raman Scattering in Vitreous Silica, Phys. Rev. B, Vol.12, p.2432 (1975)

Low-Temperature Specific Heat and Thermal Conductivity of Non-Crystalline Solids, PRL, Vol.27, p.1280 (1971)

The concensus of these works is a clear indication of dynamic non-equilibrium behavior of non-crystalline silica (the most basic glass former known) at the molecular level. This would indicate some degree of irreversible (plastic) deformation on the smallest spatial scales. The net result of this over time would most likely be irreversible (plastic) deformation on continuously larger spatial scales. -- logger9 (talk) 01:11, 19 March 2009 (UTC)

"...This would indicate some degree of irreversible plastic (structural) deformation -- and flow -- on the smallest spatial scales." I don't disagree that atoms often rearrange in glasses... but that happens in all solids, crystalline or not. You seem to be concluding that the deformation will result inevitably in crystallization, and I respecfully disagree that the dots can necessarily be connected to draw that picture. Academically, this would be the equivalent of the conclusion/myth that old cathedral windows are thicker on the bottom because the glass has been pulled down due to gravity over the years... based on the archaic idea that glass "flows" in one way or another even below Tg, in some mysterious way that makes it different from flow/diffusion/defomation in crystals. The mechanism may be different, but that does not make it any less stable (over trillions of years anyway) than crystals nor does a different mechanism somehow not fulfill the definition of a "solid." It is scientifically inappropriate to draw such a conclusion, and inappropriate in this setting to state so in an article as that would be considered original research or opinion. Njsustain (talk) 12:28, 19 March 2009 (UTC)

You wrote: "I don't disagree that atoms often rearrange in glasses... but that happens in all solids, crystalline or not."

I was waiting patiently for someone to point out that fact ;-)

Notice that I have not (yet) made this statement in the article, nor have I (yet) used these references -- partly for the reasons that you state here. But I would like to point out that plastic deformation in crystalline solids is highly localized due to the extremely finite and localized distribution of point and line lattice defects, and their limited mobility at most temperatures. Amorphous solids, on the other hand, consist largely of defects (by definition). Thus, such irreversible deformation is much more likely to occur throughout the entire structure, and potentially on a much larger length scale. -- logger9 (talk) 20:14, 19 March 2009 (UTC)

In common SiO2-glasses Avramov et al. (I. Avramov, C. Rüssel, R. Keding: "Effect of chemical composition on viscosity of oxide glasses"; J. Non-Cryst. Solids (2003), vol. 324, p 29-35) talk about a "lubricating effect" of silicate groups with non-bridging oxygen atoms to explain the viscosity behavior in SiO2-glass with small impurities. I did not hear about similar effects from crystals yet. Another phenomenon in glasses is the mixed-alkali effect, that, as far as I know, is explained by the fomation of channels within the SiO2-network as soon as alkali ions occur (pathway model by M. D. Ingram, A. Bunde and others). Again, I do not know about such rearrangements in crystals. --Afluegel (talk) 20:55, 19 March 2009 (UTC)

Actually, the two effects might be related, see [1] --Afluegel (talk) 05:03, 20 March 2009 (UTC)

Superb website w/ some very interesting references -- logger9 (talk) 06:35, 20 March 2009 (UTC)

Structure in Liquids and Glasses

Be sure to check out the recent additions to the article. I will try to get the references (listed as "More references") inserted appropriately -- as per Wikipedia guidleines -- as soon as possible. -- logger9 (talk) 20:59, 20 March 2009 (UTC)

I would like to see some more on the structural characterisation of liquids and glasses by experiment, e.g. by neutron and x-ray diffraction methods. Some of this could be wikilinked to new articles on the subject. Jdrewitt (talk) 09:08, 30 May 2009 (UTC)

Notes on the article

Thank you Logger9 for sharing your knowledge with us. After taking some time to review this article, I have a few suggestions and questions. I’ll start with the suggestions, but please keep in mind that any criticism is only intended to be helpful, and constructive to the article.

“Since the early theoretical and experimental investigations on polymorphism and the various states of aggregation which can be assumed by a given substance, the vitreous state of matter has been recognized as having the mechanical response of both solid and liquid, depending on the time and length scale under consideration.” I had to read this sentence three times before it began to make sense. I think a sentence like this could be simplified a little without losing any content. Perhaps something like: Since early investigations on polymorphism, and the various states of particle aggregation, (which can be assumed by a given substance), the vitreous state of matter has been recognized as having the mechanical response of both a solid and a liquid. It’s not much of a change, but sometimes punctuation can make all of the difference. (Note, this exact same sentence appears at least twice, once in the introduction and once in the vitrification section.) [Actually, after reading this again, I think removing the phrase in paranthesis vastly improves the readabilty, without any real loss in content, but that's just a suggetion.]

When I come across a word that is not normally used in common speech, I usually look for a more common alternative. While having a large vocabulary is always a plus, I think an encyclopedia article should be written with everybody in mind, and should be made as clear as possible. For instance, I am not an atomic physicist and had to look up the particular meaning of aggregation, as used above, which should be linked to the wiki article Particle aggregation. While this is unavoidable, a word such as “elucidate”, while a perfectly valid word, should be replaced with a more common alternative, such as “clarify”.

An encyclopedia article should never proclaim its purpose. While an “abstract” is common in scientific papers, they aren’t usually found in encyclopedias. The purpose of the article should be no more than is described in the title, to provide information about the physics of glass. For an article to have a purpose of pushing a viewpoint is in violation of WP:NPOV. Although it should be noted that you are clearly trying to show both views, the entire last paragraph of the introduction section serves no real purpose here. That makes the article read like a textbook, and the purpose of an encyclopedia is to relay facts, not to teach.

Much of the article is beyond my comprehension, so far. I may have to read through it a few more times. It might help to start each section with a paragraph that summarizes the section in a brief but concise format.

To me, common sense would indicate that glass is a solid, although if it would ‘attempt’ to crystallize over a span of time I could see where that would give it the appearance of a liquid. To me, anything on a time scale other than what we can perceive is “uncommon sense”, (a sensory ability that we as humans do not possess). I am curious to find how this compares to steel which has been heated above the austenite transformation temperature, in which crystals form, (and grow with increasing temperature), and carbon atoms move freely in and out of “solution”, but the material is still clearly a solid far below its melting point. (I sort of like the “water balloon” theory myself. A water balloon is a solid object, completely self contained, even though its internal structure is a liquid, a water balloon deforms but does not flow.)

I hope what I have said helps to improve the article, keeping in mind that this is not a forum to discuss the subject itself. I think some simple language improvements could make it a little more understandable. Zaereth (talk) 19:29, 6 May 2009 (UTC)

Red Links

User:Headbomb, greetings. My reading of WP:RED is that red links are to be used for short time increments to link to articles which are being actively developed and not as place holders for articles which might or might not be written. I've been following this particular article for some time and have not seen the red links disappear with any significant regularity so can assume that the linking articles are not being actively developed. Since you and I disagree as to the intent and meaning of WP:RED and about my revision I would humble ask that you give sufficient time for other editors to weigh in with their opinions before reverting again. I agree that the links aren't broken in and of themselves but they link to nonexistent articles.

One alternative suggestion might be that you might wish to write an article entitled [[Lexicon of glass physics terms]] or similar to contain the links if you don't have the time to write articles about each individual red linked term. Regards.Trilobitealive (talk) 00:05, 30 May 2009 (UTC)

(See Wikipedia:Linking#Internal links: overlinking and underlinking for further insights. I realize that in part it negates my specific assertion but it provides further insight into the general considerations.)Trilobitealive (talk) 00:11, 30 May 2009 (UTC)

All the links I made can be expanded into legitimate articles, or redirect to an appropriate topic, which would possibly something like Lexicon of glass physics terms, but not necessarily. WP:REDLINK states "Sometimes it is useful in editing article text to create a red link to indicate that a page will be created soon or that an article should be created for the topic because it would be notable and verifiable." If one of the links I made isn't notable or vefiable, then go ahead and remove it, but I'll doubt you'll find any which don't meat notability and verifiability criterions.

It appears you are hinging your action on the concept that ...sometimes it is useful in an article to create a red link... and the misapprehension that somehow the reader must assume notability and verifiability without sources. I'm sorry but if there were links to sources then the links would not be red. I removed the links because they were neither notable nor verifiable without supporting articles.Trilobitealive (talk) 03:54, 30 May 2009 (UTC)

Also it is not true that you have been watching this articles and that these are 3 centuries old links, you waited about 15 hours at best, which is not a lot of time by anyone's standard, and it certainly is puzzling that you were somehow able to determine my intentions to not create those article in such a short period of time. I also do not agree with your statement that the page should be locked to your version until someone else disagrees with you. This is not how Wikipedia works. See WP:OWN. Headbomb {^ταλκ_{κοντριβς} – WP Physics} 02:05, 30 May 2009 (UTC)

Ah, such hyperbole is really unneeded. We should try to stick to what has been said rather than making things up. I merely reverted what appeared to be edits which detracted from the quality of the article. The red links make these sections look like they are link graveyards (see WP:MOS#Links). To quote from that policy: "It is not useful and can be very distracting to mark all possible words as hyperlinks. Links should add to the user's experience; they should not detract from it by making the article harder to read. A high density of links can draw attention away from the high-value links that you would like your readers to follow up. Redundant links clutter the page and make future maintenance harder..."

To make the article more readable you need to create links which have meaning to the reader. If the links are truly notable then they should be relatively easy for you to correct. But until that happens they detract from the article. Regards.Trilobitealive (talk) 03:54, 30 May 2009 (UTC)

There is nothing wrong with having redlinks in an article. If there are too many, say more than 5% (arbitrary value) of the wikilinks are red then yes I would agree that some would have to go. But that is not the case here. A redlink is an excellent indicator as to what areas of wikipedia require expansion and give editors the ability to create new articles which are actually needed! I see no evidence of Headbomb "making things up" and it is in fact comments like those that are uncessary and unconstructive. Jdrewitt (talk) 09:03, 30 May 2009 (UTC)

User:Jdrewitt, if you require evidence as to the veracity of my statement about making things up please refer to Headbomb's twin assertion that I've not been truthful when I stated I'd been watching the article and his hyperbole about 3 century old links. HIs comment wasn't constructive nor, I admit, was my reply, nor was your comment so perhaps we should abandon that direction of discussion?

Back on topic please refer to WP:N and WP:V.(Headbomb tried to provide external links to these pages above but for some reason, possibly my use of Firefox, I can't get them to work so I'll just provide internal links.) Material which cannot be directly verified as notable should not be in Wikipedia so perhaps the red linked material should be removed entirely until further support can be gathered for it's notability and verifiability? This is a 90 kb article which still retains a class C assessment. Could the red links be a symptom of a greater problem, that of an heroic attempt to create one single overwhelmingly complete article rather than multiple smaller articles?

Personally I enjoy reading original research, but Wikipedia doesn't have any place for it even if the edits are written by an expert in the field. Wikipedia doesn't assume the existence of anything unless it can be externally verified and these particular red links emphasize a relative lack of verification of their targets. Regards.Trilobitealive (talk) 22:43, 30 May 2009 (UTC)

The red links are not the problem here, if the material is not verifiable then that is a more general issue requiring e.g. more citations or explanation of the terms in order to make the article more accessible to the general reader. I agree there are problems with this article in that it is way too technical for the general audience and have asserted this from the day the article was created (Which incidently was very recently so no you cannot have been watching this article for very long). However, wikipedia doesn't cover everything and hence sometimes redlinks just happen. As I said before these are an indicator to other editors as to what topics need expansion giving them the chance to create articles that are actually needed. Jdrewitt (talk) 13:04, 31 May 2009 (UTC)

Well, before deleting the red links, perhaps a little investigation into them may provide an alternative link. For instance, the red-link atomic ratio could easily be linked to the existing wikipedia article atomic percent. Or, better yet, a redirect for atomic ratio could be made for that page. Often it's as simple as googling the phrase with "wiki" added, (eg: google: atomic ratio wiki), to come up with a useful link. If there is no article to link it to, but it's obvious what the link means, there is no need for an explanation, (ie, an exerpt from the Dogfight article: "A pilot who realized that new tactics had to be devised was Lieutenant Commander John S. "Jimmy" Thach, commander of Fighting Three in San Diego." It's pretty ovvious here what the red link here means.) If a word is used that is not likely to be understood by a majority, whether red-linked or not, then a small parenthetical explanation may be in order. (ie, an exerpt from the Flashtube article: "Optimum output efficiency in the visual range is obtained at a density that favors "greybody radiation" (an arc that produces mostly continuum emission, but is still mostly transparent to its own light).")

I agree that too many red links become a distraction from an already confusing article. This article could use more blue-links to articles such as I've mentioned in the section above. I also agree that it is far too technical, as per my comments above. I'd love to help with that, in my limited time, but but lack of thorough understanding of this article prevents me from making constructive grammar and syntax changes without fear of altering some content unintentionally. I'd really like to understand it, though. Zaereth (talk) 23:50, 1 June 2009 (UTC)

There is nothing wrong with red links per se. Red links should always be evaluated by looking at the target phrase. If the target phrase is a valid subject for a Wikipedia article, the red link should stay. If the target phrase is not a suitable subject, the link should be removed or changed to point elsewhere. If the target of the red link is a valid article topic, but an article exists at some other name, create a redirect. If the target of the red link is not quite a valid topic, consider changing the link to point to a more suitable article. Under no circumstances should a red link be removed merely because it is red.--Srleffler (talk) 15:01, 27 June 2009 (UTC)

off-topic section

Section on "viscosity of simple liquids" should be removed. This article is about glasses, not liquids, right ? -- Paula Pilcher (talk) 10:16, 26 June 2009 (UTC)

Wrong. Glasses behave as both solids and liquids -- as described in the article. -- logger9 (talk) 21:50, 26 June 2009 (UTC)

The article Liquid would be greatly improved if this material is added. It is a shame to "hide" it from a reader who is looking into the physics of liquids without necessarily being concerned with glass. Cuddlyable3 (talk) 10:44, 28 June 2009 (UTC)

External link to a CV

Why does the article need an external link to the CV of John D. Mackenzie ? He is a distinguished professor of materials science but not (yet) a notable person. I suggest we remove this link. Cuddlyable3 (talk) 11:26, 27 June 2009 (UTC)

Removed. Even if Mackenzie were notable, it would not be appropriate to link to his CV.--Srleffler (talk) 14:56, 27 June 2009 (UTC)

name removed

To avoid mistakes about personalities, Logger9 who is one of the outstanding Wikipedia editors of the article has chosen to identify himself (on his user page via own website as name removed Cuddlyable3 (talk) 11:42, 27 June 2009 (UTC)

It is not appropriate to name users without their consent, see the policy WP:OUTING. I have hence removed your post, if Logger9 feels it is ok to reveal information about their own identity then this should be their decision and no one elses. I'm not saying you have done this maliciously, only that it is unecessary and inappropriate. If Logger9 feels otherwise then they are free to revert my edit to this page. Jdrewitt (talk) 17:15, 27 June 2009 (UTC)

Thank you Jdrewitt for directing me to the policy WP:OUTING. In this case Robert Allman, Jr chooses to identify himself and his website explicitly on Logger9's user page ('my website...About the author') so we have his consent. It is not necessary for any Wikipedia user to give their identity but I think they are free to do so, whereupon the WP:OUTING policy cannot apply. Mr. Allman clearly is an outstanding editor here and he is presently credited under several of the illustrations (but see recent edits). Thank you for granting me WP:AGF. In fact I have repeated information that is present elsewhere in Wikipedia on to this page, and it can be appropriate in resolving any questions about WP:COI that arise. Mr. Allman acts correctly in being open about his professional involvement. Cuddlyable3 (talk) 10:35, 28 June 2009 (UTC)

I disagree, it is not your place to do this and see no evidence of a conflict of interest. I also cannot see anywhere where Logger9 explicitely declares their identity except by directing from their talk page to their website. But they haven't actually stated their identity on wikipedia pages. I will leave this for now, if Logger9 objects to their identity to being revealed then I will strongly support them. Jdrewitt (talk) 11:12, 29 June 2009 (UTC)

I have to admit that all this has me a bit confused. I really would prefer to keep my real identity out of all this, especially considering the recent personal attacks on my work and reputation by one paricular overzealous editor.

I have only recently added my name to my webiste after being asked by the institution where I teach to include a section "about the author". It is strict policy that studetns at my university are not encouraged to use information they find on websites unless they have specific information regariding the quality of the author(s) and/or other sources. Thus, the section was recetnly added so that I could freely use the website as s supplemental teaching aide -- which is precisely why I have spent much of the lsst ten years of my life composing it (link by bloody link!).

But now, I must admit, if this becomes a serious issue, then I will imimediately remove my name from it. But I will need to understand a bit more about the issues here before I act. -- logger9 (talk) 17:19, 29 June 2009 (UTC)

Vitreous state

Editors of this article may be interested in the discussion at Talk:Vitreous state, about what to do with the articles Vitreous state and Glassy state.--Srleffler (talk) 14:50, 27 June 2009 (UTC)