Gamma irradiation effect towards photoluminescence and optical properties of Makrofol DE 6-2

Abstract

The optical, Raman and Photoluminescence properties of Makrofol DE 6-2 polycarbonates were explored in detail. A set of polymeric Makrofol samples were subjected to γ-ray source at various doses ranging between 1 and 200 kGy. UV–Vis spectra depicted that Makrofol DE 6-2 has a high absorption maximum band at about 230 nm and decreases sharply at about 285 nm. The optical energy band gap was calculated using different methods, Ineffective Thickness Method (ITM), Derivation of Ineffective Thickness Method (DITM), Absorption Spectrum Fitting (ASF) and Derivation of Absorption Spectrum Fitting (DASF) methods. All used methods revealed an observable decrease in the optical energy band gap values with increasing gamma irradiation doses for both the indirect and direct transitions, whereas the refractive index showed the reverse trend. Also, the photoluminescence intensity decreases with increasing gamma dose up to 200 kGy due to formation of defects. Peaks at 884, 1364, 1394 and 1854 cm−1 are registered corroborative its structure in the Raman spectrum. Its intensity showed a decrease with increasing the gamma dose which may be attributed to the formation of non-irradiative levels as a result of degradation. Color change of the polymer from transparent to faint yellowish after γ-irradiation of doses higher than 1 kGy was observed which may be due to formation of color centers appeared in the range 305–315 nm. The present results should be taken into account before utilization of Makrofol DE 6–2 in photoelectric devices and medical applications related to gamma radiation.