A new clue in the glass puzzle

A new clue in the glass puzzle

December 9, 2014
in Category: Physics
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A new clue in the glass puzzle
Stained glass windows in old churches appear to have thicker solid panes of glass at the bottom than at the top, as if glass flowed slowly. EU-funded physicists are working on the glass puzzle: is it a solid or merely an extremely slow moving liquid?
Glass forms through vitrification, a process where a glass-forming liquid cools down and becomes a solid, whose molecules are impermanently locked into a crystal structure. Glass is a type of amorphous solid — a state somewhere between solid and liquid states of matter — that includes common window glass.To elucidate the molecular processes occurring during vitrification, the ‘The energy landscapes of metastable states of supercooled liquids‘ (EL-GLASS) team used advanced computational techniques. Monte Carlo simulations allowed to sample the phase space so that scientists could represent all possible states of glass.Researchers compared various algorithms to optimise parameter determination. With these tools at hand, the EL-GLASS team added a new wrinkle on an old model that seems to improve how well it mimics the behaviour of glass. In the so-called random first-order phase transition model, the glass-forming liquid is composed of glassy clusters continually created and destroyed. Below approximately two thirds of the freezing temperature, they found that the size of glassy clusters becomes bigger than a certain length scale.Specifically, as glassy clusters become big enough, they behave in many ways like a solid. Their length scale was calculated through extensive research on liquid cavities surrounding frozen particles. Based on laws of thermodynamics that govern the properties of particles in liquid and solid state, it is a key component of the model distinguishing it from competing theories.

Not surprisingly, glassy liquid crystals are an emerging class of photoelectronics materials. They are characterised by superior optical quality over a large area with no grain boundaries. The EL-GLASS project has significantly contributed to efforts devoted in recent years to developing glassy materials with superior morphological stability.

Provided by Cordis


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