Cracking a controversial solid state mystery

Feb 06, 2009

(PhysOrg.com) -- Scientists can easily explain the structural order that makes steel and aluminium out of molten metal. And they have discovered the molecular changes that take place as water turns to ice. But, despite the fact that glass blowers have been plying their trade since the first century BC, we have only just begun to understand what makes molten glass solid.

One hundred and fifty years after the construction of Crystal Palace at the Great Exhibition, scientists at The University of Nottingham and the University of California, Berkeley in collaboration with the University of Bath, have presented an explanation of how atoms behave as glass cools and hardens. Their research has just been published online in Science Express, in advance of publication in Science.

The secret of glass making came to Britain with the Romans in 55 BC. But only now do scientists believe they are a step closer to unravelling the controversy that surrounds the question: what makes solid glass different from the molten liquid from which it is formed?

Juan Garrahan, Professor of Physics, in the School of Physics and Astronomy at Nottingham said: "Snapshots taken with x-rays show that in ice, water molecules fit together in an ordered array, which is called a crystal, while in liquid water, the molecules are jumbled. Scientists can understand why ice is rigid and liquid water is fluid largely from these structural differences. Glass, on the other hand, does not offer this explanation because a snapshot of the molecular structure of solid glass is almost indistinguishable from that of the molten liquid. Both appear to be jumbled random collections of atoms. This observation is at the heart of the problem: if the solid state of glass has a molecular structure just like that of the liquid, how can it be so rigid? Controversy has resulted from the absence of a clear answer to this question."

Using computer simulations, researchers were able to test the theoretical and computational process of melting and hardening glass. They have not yet solved the glass transition problem however they have provided evidence for a new perspective on glassy phenomena which may eventually lead to its solution.

Dr. Robert Jack, from the Department of Physics at the University of Bath, said: "By focusing on the ability or inability of molecules to flow we have provided evidence for a new kind of sudden transition between the flowing liquid and the solid glass. This transformation is apparent only when the system is viewed in both space and time."

Ultimately, the answer is important because the principles that underlie the glass transition can guide scientists and engineers towards methods for producing better glass — stronger and longer lasting. Disordered glassy solids are ubiquitous in everyday materials including ceramics and plastics. For over a century, principles of thermodynamics have aided the design of ordered solids, materials like steel and aluminium alloys. No such principles are yet settled for production of glassy solids. The current work is believed to be a significant step towards these principles.

Provided by University of Nottingham

Explore further: The unifying framework of symmetry reveals properties of a broad range of physical systems

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User comments : 6

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Alexa
1 / 5 (4) Feb 06, 2009
Space-time transitions are quite common in Aether thermodynamics of unsteady state phenomena.

But for explanation of glass-solid transition such approach may be too heavy gun for killing of mosquito. Solidification of glass is basically a a polymerization under formation of oxygen bonds, where the average molecular weight increases with decreasing temperature by Maxwell-Boltzmann statistics. It's not accident, behavior of glass is simmilar to behavior of thick polymer solutions.
Alexa
1 / 5 (3) Feb 06, 2009
High viscosity of molten glass with compare to water is the result of fact, each structural element of silicate glass has 2 - 2.5 oxygen bonds available, which enables a much stronger crosslinking of resulting structure - then in the ice, where each molecule of water has just about 1.5 oxygen bonds available per single molecule.

http://www.emeral...3008.png
kniedzius
5 / 5 (1) Feb 12, 2009
Yeah.. Aether-wave this and aether-wave that until everybody understands that some amateur mumbo jumbo is suddenly the most unified theory of the universe!
Ceramic_Engineer
5 / 5 (1) Feb 12, 2009
Alexa,
The structural basis of glass is tetrahedrons with Si in the middle and O at the 4 minimum energy sites surrounding Si atom. The real world is not 2D as the internet may have you believe. My teachers for glass science were the most highly respected people in the field and they all admit to not understanding what is really going on. Also water is a very poor model for most glass formers because it is very fluid right up to its solidification point. Making glass is an example of kinetics beating out thermodynamics. I have had graduate thermo and there is no Aether theory in respect to real world materials.
Alexa
1 / 5 (2) Feb 12, 2009
..they all admit to not understanding what is really going on..
I can't believe it. Glass melting is apparent depolymerization.

Aether thermodynamics is extended to time dimension, it describes non-equilibrium phenomena like steady state ones.
mikmik
not rated yet Feb 25, 2009
I can't believe it. 'Solid' glass is amorphus.

"Space-time transitions are quite common in Aether thermodynamics of unsteady state phenomena."
I just had a space-time transition, which is quite common when you move, or even don't move.
I am allergic to aethur-waves. This why I always carry my space-time transformation serum.

"The real world is not 2D as the internet may have you believe."
Yeah, and next you have me believing that the internet gets hurt feelings when I swear. I think the internet needs some heavy counselling, not mention heavy medications. If the internet doesn't want the medications, then I will take them.

Question? Why the heck would you think that anyone here would conclude that the internet makes anyone over the age of shadow think the world is 2D? I am apprehensively sure that not one single person over the age of blastoma thinks the worls is 2D.

What the f*** do new age transformations think that anyone witha kindergarten education or better are in need of instruction about Dirac charcters.