What makes solid glass different from the molten liquid from which it is formed

February 7th, 2009 - 4:12 pm ICT by ANI  

Washington, Feb 7 (ANI): Scientists have cracked a controversial mystery of what makes solid glass different from the molten liquid from which it is formed, by presenting an explanation of how atoms behave as glass cools and hardens.

The team of scientists is from the University of Nottingham and the University of California, Berkeley in collaboration with the University of Bath.

Though 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?

According to Juan Garrahan, Professor of Physics, in the School of Physics and Astronomy at Nottingham, 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, said Garrahan.

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, he explained.

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.

According to Dr. Robert Jack, from the Department of Physics at the University of Bath, 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.

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. (ANI)

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