Heat capacity at the glass transition

A fundamental problem of glass transition is to provide a quantitative and microscopic explanation of the heat-capacity jump at the glass transition temperature Tg . Similar problems are also common to other disordered systems, including spin glasses. We propose that the jump of heat capacity at Tg takes place as a result of the change of the liquid’s elastic, vibrational, and thermal properties. In this theory, we discuss time-dependent effects of glass transition, and identify three distinct regimes of relaxation. Our approach explains a widely observed logarithmic increase of Tg with the quench rate and correlation of the heat-capacity jump with liquid fragility.