A single-frequency test for one-parameter models of the linear thermo-visco-elastic response of glass-forming liquids

Abstract

A master equation description of the inherent dynamics is used to calculate the frequency-dependent linear thermo-visco-elastic response functions of a glass-forming liquid. From the imaginary parts of the isobaric specific heat, isothermal bulk modulus, and isobaric thermal expansion coefficient, we define a quantity $\Lambda_{Tp}(\omega)$ with the property that $\Lambda_{Tp}(\omega)=1$ is equivalent to having a one-parameter description of the linear thermo-visco-elastic response. This provides an alternative to the well-known criterion based on the Prigogine-Defay ratio.