Abstract: | The effects of temperature and pressure on the shift factor and the dielectric increment of the β relaxation process were measured for vulcanized chlorinated polyethylene. The isobaric and isochoric activation enthalpies, H*P and H*V, the activation volume V*, the pressure dependence of the glass–glass transition temperature, Tgβ/dP, and the apparent extinction temperature T0β were obtained. The pressure dependences of both V* and the dielectric increment would reach very small values near the liquid–glass transition temperature Tg, and the β process seems to be affected by the transition near Tg. The value of H*v/H*p for the β process is larger than that for the α process, and it is suggested that the molecular motions pertaining to the β process are more strongly restricted than those pertaining to the α process. The ratio T0β/T0, where T0 is the characteristic temperature in the Vogel–Fulcher–Tammann–Hesse equation for the α process, follows the empirical relation of Matsuoka and Ishida, Tgβ/Tg ~0.75. The value of dTgβ/dP estimated from Tg and T0β/T0 is consistent with the experimental value. |