Polyethylene glycols and polypropylene glycols were irradiated with gamma-rays from a 60Co source at 77°K. Electron spin resonance spectra of the free radicals produced were recorded. It was found that the rupture in the polymer chain takes place at *C? C and C? O bonds. The radicals identified were ? O? CH2 in polyethylene glycols and mainly in polypropylene glycols. Thermal decay of these radicals followed a second-order law, and the decay constant calculated was k = 2.32 × 105 cm.3 mole?1 sec.?1 A complete discussion of the results is presented.
