Temperature dependence of the dielectric relaxation processes in glass-forming materials

Abstract

For some glass-forming substances the limiting temperature, T^′_g, of the power-law equation ƒ_m∝(T–T^′_g)^r, where ƒ_m is the maximum loss frequency, is shown to correspond to the temperature, T₂, of Gibbs and Demarzio theory. The spectral shape parameters (1 –m), n of the Dissado–Hill expression is found to vary linearly as log (T–T^′_g) at temperatures above the glass-transition temperatures. The consequences of this relation on time–temperature superposition principle are discussed.