Effect of pressure and temperature on the secondary relaxation in vinyl chloride-vinyl acetate copolymer films by the PSD and TSD current techniques

A relaxation in the glassy state has been observed in the poled vinyl chloride-vinyl acetate copolymer film by using the piezo-stimulated (PSD) as well as the thermally stimulated depolarisation (TSD) current techniques. The observed relaxation peak has also been studied as a function of poling temperature, field and the applied pressure. The relaxation time is a linear function of pressure and temperature, whereas the displacement coefficient of the peak with temperature and pressure is quite small and the ratio of the Delta V*/Vm is less than unity. The PSD results agree fairly well with those calculated by analysing the TSD current peak.