The Theory of Glasses: The Last Twenty Years (Mostly)

The mosaic picture of supercooled liquids and glasses based on an underlying random first order transition provides a comprehensive framework for understanding a wide range of nonequilibrium phenomena. Twenty years ago, going beyond scaling analyses, an approximate molecular level theory was developed that rationalizes the concept of “fragility” in explaining the universal rules behind the chemical diversity of glassy dynamics. The success of the quantitative predictions of this theory for activation barriers, dynamical spatial correlations and the nonexponentiality of relaxation in supercooled liquids is reviewed. Within the glassy state, the theory has also predicted many surprising quantitative relationships between aging, jamming, rejuvenation and the mechanical behavior of glasses, including shear banding. The comparison of theoretical predictions with laboratory experiments will be highlighted.