On the estimation of the Kauzmann temperature from relaxation data

Abstract

The well known WLF equation describing the relaxation behaviour of glass-forming liquids near the glass transition temperature has been rederived on the basis of Adam and Gibbs' excess entropy model, making use of a novel expression for the entropy of undercooled liquids. It has been shown that C₂ in the WLF equation is a nearly constant fraction of (T_s - T₂), where T_s and T₂ are the reference and the Kauzmann temperatures, respectively. It is demonstrated that the values of T₂ obtained from the relaxation data agree well with those calculated from thermodynamic data. The arguments used provide an explanation for the universality of the WLF constant, C₂.