ESR study of pressure and temperature dependence of free‐radical decay in poly(vinyl chloride)

Gamma‐irradiated poly(vinyl chloride) was annealed at various temperatures (80 to 140°C) and pressures (0.1 to 800 MN m −2 ). Rate constants and activation volumes of free‐radical decay were determined from the changes of the electron spin resonance (ESR) spectra before and after annealing. The pressure and temperature dependence of the rate constant is compared with the pressure and temperature dependence of the mechanical relaxation parameters. The correlation between the kinetics of radical reactions and the kinetics of the molecular motions in the α‐relaxation region is discussed.