Pressure effect on relations between glass transition temperature and freezing-in rate for polystyrene

Glass transition temperature, Tg , was determined for an anionic polystyrene by using an integral method from DTA data obtained at 0.1 and 400 MPa. Tg decreased as the rate of cooling through the glass transition region was lowered. The gradients over 1 K/h to 20 K/min were 2.24 K/decade at 0.1 MPa and 1.51 at 400 MPa. In order to get an insight in the number of internal order parameters that govern the glassy state, the data were compared with the p-v-t data reported by Oels and Rehage (ref. 15).