Thermodynamical Scaling of the Glass Transition Dynamics

TL;DR

This paper introduces a generalized thermodynamical scaling law for glass transition dynamics, demonstrating that relaxation times of various glass-formers can be superimposed using a material-specific exponent gamma, highlighting the role of volume in the process.

Contribution

It proposes a new scaling law, log tau proportional to T^(-1)V^(-gamma), that unifies the description of glass transition dynamics across different materials.

Findings

Superpositioning of relaxation times for ten glass-formers using the scaling law.

The exponent gamma indicates the influence of volume over thermal energy.

The scaling applies to van der Waals molecules, associated liquids, and polymers.

Abstract

Classification of glass-forming liquids based on the dramatic change in their properties upon approach to the glassy state is appealing, since this is the most conspicuous and often-studied aspect of the glass transition. Herein, we show that a generalized scaling, log tau proportional to T^(-1)V^(-gamma), where gamma is a material-constant, yields superpositioning for ten glass-formers, encompassing van der Waals molecules, associated liquids, and polymers. The exponent gamma reflects the degree to which volume, rather than thermal energy, governs the temperature and pressure dependence of the relaxation times.