Color changes and optical properties of gamma irradiated polycarbonate/poly(methyl methacrylate)/polyvinyl chloride blended polymers: Linear and nonlinear optical parameters

The casting approach was applied to create blended polymers of polycarbonate, poly(methyl methacrylate) and polyvinyl chloride (PC/PMMA/PVC). Several gamma radiation doses (20–150 kGy) were utilized to irradiate samples from the produced PC/PMMA/PVC films. The consequent influences of the gamma radiation on the color changes, linear and nonlinear optical parameters of the created films were explored by means of UV-spectroscopy. Also, the International Commission on Illumination (CIE) color differences approach was utilized to evaluate the color shifts amongst the films irradiated with different doses and the non-irradiated one. The gamma irradiation with doses ranging between 20 and 150 kGy caused noticeable color modifications to the colorless pristine film due to the tendency of the green and blue color components to be converted into red and yellow, respectively. This caused an increase in the color intensity to 28.32 indicating significant color changes. Moreover, the blended polymers’ absorbance increased when irradiated with gamma doses up to 150 kGy. Also, the values of Urbach energy were enhanced from 0.11 to 0.26 eV. Additionally, the direct and indirect bandgaps decreased from 4.72 to 4.25 eV and from 4.52 to 4.05 eV, respectively. Furthermore, we identified the kind of microelectronic transitions for the PC/PMMA/PVC blended polymers utilizing the optical dielectric loss function (ε"). We detected that the type of transition is a direct allowed. Moreover, the refractive index increased from 2.043 to 2.123 upon γ irradiation up to 150 kGy. The resulting improvements in optical characteristics of the PC/PMMA/PVC blended polymers introduce the basis that can be used in constructing optoelectronic devices.