Interferometric investigation of the effect of gamma radiation on the refractive index of CR-39 polymer

A non-contact and simple interferometric technique has been used to measure the refractive index variation of gamma irradiated CR-39 polymer samples. Six samples of thickness (750 mu m) and dimensions of 1.5 x 3 cm(2), have been irradiated with gamma radiation doses in the range from zero to 600 kGy. It is observed that the refractive index increases by increasing the dose and reaches its maximum value at 40 kGy dose, and then starts to decrease again. This means that the gamma radiation deformation in the CR-39 polymer is a chain scission effect. This interferometric technique could make a contribution to recombination and degradation mechanisms on CR-39 polymer. Copyright (C) 1996 Elsevier Science Ltd.