Connection between the glass transition temperature Tg and the Arrhenius temperature TA in supercooled liquids

At high temperatures the structural relaxation time in liquids has Arrhenius temperature dependence. At lowering temperature, temperature dependence changes to a super Arrhenius at some temperature T-A. This temperature is an important point for the structural relaxation dynamics in supercooled liquids because it reflects the transition to collective relaxation. Here we derive a relation between T-A, the glass transition temperature T-g and fragility. We show that the ratio T-g/T-A increases with increasing fragility of a liquid. The derived relation is in agreement with the experimental data in a series of molecular, hydrogen bonding and two inorganic glass-formers. (C) 2016 Elsevier B.V. All rights reserved.