Kinetics of structural relaxation of poly(ethylene terephthalate)

The results of an experimental study of the kinetics of structural relaxation of amorphous poly(ethylene terephthalate) are reported. Samples were prepared by ultraquenching the melt on rotating stainless-steel discs. Two types of measurements by differential scanning calorimetry were made: (1) the dependence of the “fictive” (or “structural”) temperature Tf(q−) introduced by Tool, on the cooling rate q− and (2) the dependence of the glass transition temperature Tg on the heating rate q+. In this way the value x = 0.47 was obtained for the dimensionless parameter proposed by Narayanaswamy.