Response to “Comment on ‘Direct determination of the fragility indices of glassforming liquids by differential scanning calorimetry: Kinetic versus thermodynamic fragilities’ ” [J. Chem. Phys. 118, 10351 (2003)

Abstract

We give a brief review of how activation energies from scan-rate-dependent Tg studies have been correlated with those for viscosity and other relaxation processes, in order to place the present study in context with previous work, including that referred to in the comment. Then we examine the ensuing question of the extent to which kinetic fragility can be predicted from thermodynamic data. We present a new correlation involving only the entropy of fusion and the jump in heat capacity at Tg, that is followed by most nonchain liquids. Polymer liquids, as the comment authors have shown, have different behavior, consistent with earlier failures to identify Kauzmann and Vogel temperatures in these materials.