Temperature-Volume Entropic Model for Viscosities and Structural Relaxation Times of Glass Formers.

In this Letter, an entropic model recently formulated by Mauro et al. for the temperature dependence of viscosity in glass-forming materials is generalized to describe the temperature-volume dependences of viscosities and structural relaxation times near the glass transition. It is found that the generalization shows limitations of its temperature precursor. The extended model describes well the structural dielectric relaxation times τα(T,V) of supercooled van der Waals liquids. The obtained results are discussed in the context of the thermodynamic scaling law for molecular dynamics of viscous systems.