Glass is so poorly understood that if a transition occurs it is far from universally accepted. It is said that “there are more theories of the glass transition than there are theorists who propose them”.

During a scientific revolution, many interpretations of what is happening compete before one interpretation becomes accepted by the scientific community as being correct. In this respect, our understanding of what happens when a liquid is cooled, whether it forms an “ideal glass”, is undergoing a modern-day scientific revolution.

The reason it is hard to observe a liquid transforming to a perfectly solid “ideal glass” is that to do so we would have to wait an extraordinarily long time (much longer than centuries) because the process is very slow. But the behaviour of viscous liquids is more surprising than simply having to wait a long time.

If we look at the microscopic behaviour of small groups of molecules, viscous liquids seem to find it hard to make up their mind whether to be solid or liquid. Regions of a few tens of molecules in size are liquid-like, others are solid-like. Over time these regions change between being solid-like or liquid-like state. This is totally different to water freezing, when all the molecules together decide to form a solid.
We tried to answer this question and found a new way to understand how molecules behave in these small regions in a viscous liquid. We used information theory originally developed in Bletchley Park for code-breaking to find out how molecules in the solid-like and liquid-like regions communicate with one another. It involves the use of calculating multiple permutations and combinations of interactions between atoms, much like the permutations and combinations needed to break the Enigma code.