Complex plane analysis of heat capacity of polymers in the glass transition region

A method is described which enables the direct measurement of relaxation times and relaxed and nonrelaxed heat capacities as a function of temperature. The apparatus designed is to be used as additional equipment to the Perkin-Elmer differential scanning calorimeter DSC-1B. The specimen is heated periodically with time instead of proportionally. The amount and phase of differential heat flow are measured. The parameters of an 'equivalent circuit' of a heat capacity model are fitted to the measured complex C p values obtained at various frequencies and appropriate amplitudes of temperature. Further applications of the 'oscillating thermal analysis' are proposed.