The effect of gamma-ray irradiation on bulk optical plastic materials

We present our study of the effect of gamma-ray irradiation on bulk optical plastic materials as follows: three types of sheets commonly used for eyeglass lenses (CR-39, MR-8 and Trivex), cyclo olefin polymer ZEONEX E48R, styrene methyl methacrylate NAS21, polymethyl methacrylate PLEXIGLAS®7N, polyphenylsulfone EUROPLEX® PPSU, and poly(n-methyl methacrylimide PLEXIMID®8813. We used the panoramic gamma-radiation facility with ⁶⁰Co source with applied doses 14.6 kGy and 54.2 kGy. For the thought properties, we measured the transmission spectra from 200 to 1800 nm and refractive indices using the prism coupling technique at six wavelengths 532.0, 654.2, 846.4, 1308.2, 1549.1, and 1652.1 nm. We also studied the possibility of using several approximation methods for evaluating the refractive indices including Cauchy, Cauchy–Schott, Herzberger, Sellmeier, Sellmeier-2, and Sellmeier with an infrared correction. The measurements showed that the most precise determination model of the refractive indices was obtained by the Sellmeier approximation with an infrared correction. The transmission spectra measurement showed that the CR-39 and EUROPLEX® PPSU polymers did not change significantly after the irradiation and the refractive indices measurement showed that ZEONEX E48R and EUROPLEX® PPSU did not change the refractive indices values.