Analysis of curves of loss factor against reciprocal temperature for dielectric and dynamic mechanical relaxation

Abstract

Expressions are derived for the areas and widths of curves of dielectric or dynamic mechanical loss factor against reciprocal temperature at constant frequency. To a good approximation the area is shown to be a function of the dielectric (or modulus) increment and an average activation energy for the relaxation processes, but is independent of the distribution of relaxation times and the frequency of measurement. The widths of the curves are inversely proportional to the activation energy and a distribution parameter β, which is an empirical measure of the width of the distribution of relaxation times. It is shown that activation energies calculated from areas and widths of experimental curves agree well with values obtained from the temperature dependence of the frequency of maximum loss.