ESR studies of local concentrations of radicals in polyethylene irradiated at 1.5, 4.2 and 77 K

The microwave power saturation behaviour of alkyl radicals in polyethylene irradiated at 1.5, 4.2 and 77 K suggests that the local concentrations of radicals in spurs is considerably higher in the samples irradiated at 1.5 and 4.2 K. Upon annealing the samples at 77 K, the local concentrations became nearly the same as those of the sample irradiated at 77 K. The decrease of the local concentrations at 77 K was larger than that of the total concentrations suggesting an expansion of the initial spur at 77 K.