A detailed investigation of the gamma-ray radiation effects on the optical properties of polyvinyl butyral film

Polyvinyl butyral (PVB) films were irradiated with various doses up to 250 kGy by gamma radiation. The PVB was synthesized using solution method and in order to uniform exposure, film form of it was provided. Formation of PVB was confirmed using the Fourier transform infrared spectroscopy (FT-IR). The effects of gamma irradiation on the various optical properties of films such as absorption coefficient, penetration depth, Urbach energy, optical band gap energy, threshold wavelength, extinction coefficient, refractive index, optical dispersion parameters, dielectric constant and dissipation factor were studied by UV–vis spectroscopy. The results showed some changes in the optical properties of PVB films due to cross-linking formation between polymer chains. At doses higher than 70 kGy, however the polymer began to decompose due to chain scission and trend of the optical properties changing became inverse.