Abstract : Although poly(methyl methacrylate), PMMA, is known to degrade when exposed to ultraviolet radiation, studies at wavelengths other than 253.7 nm have not been done. The lack of knowledge about the mechanism of degradation of PMMA at wavelengths other than 253.7 nm hinders efforts to develop short-term test methods for predicting the long-term performance of PMMA in applications in which it is exposed to sunlight. This study was performed to determine the effect of ultraviolet radiation on PMMA and to identify mechanisms of degradation induced by the radiation. jg p5