Volume relaxation in simple liquids

Abstract

The volume relaxation due to step changes in the temperature of two non-polymeric glass-forming liquids has been examined, together with the viscosity transients during the volume relaxation. The results show that the material behaves as if the temperature step caused a pressure change in the liquid given by its equation of state at constant volume. The results are interpreted in terms of free volume theory. The viscosity was found to be of the form µ=At^a as expected from theory. These results suggest a simple method for obtaining both bulk and shear viscosities as a function of pressure, for low pressures.