Atactic, isotactic, and optically active poly(propylene oxides), PPOx, were irradiated with both γ‐rays and electron beams. Up to a dose of 37 Mrad no change could be detected in the optical activity. G values for hydrogen evolution decreased as compared to polypropylene in about the same ratio as G(H2) of polyoxymethylene decreased as compared to polyethylene. G values for crosslinking and scission, estimated by means of gelation theories of Saito and Inokuti, were found to be greater for isotactic than for atactic PPOx. The behavior of transient infrared and ultraviolet absorption bands is discussed. Intrinsic viscosity data indicate a rapid initial chain degradation whereas CO gas and OH group production is linear with dose. Evidence for the conversion of one type of free radical to another on heating an irradiated sample from 77°K to room temperature is based on the behavior of transient infrared and ultraviolet absorption bands.

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