Structure-property correlation study of gamma irradiated BaO-PbO-K2O-B2O3-SiO2 glasses

Lead silicate glasses were prepared and characterized for radiation shielding applications. The glass composition and processing parameters were optimised to obtain a transparent glass with required density, optical and shielding properties. The glass plates were exposed to 30 kGy of Co-60 gamma dose. Linear attenuation coefficient measured experimentally in pre- and post-gamma irradiated samples found to be almost unchanged, validating them as good shielding materials. The glasses turned brown after irradiation due to the formation of colour centres. Radiation induced absorption decreased with the addition of Ceria in the glass composition and the transparency was recovered after annealing at 300 °C temperature. Raman spectra were analyzed to derive the structural information. There was a trend of increase in non-bridging oxygen post irradiation resulting a decrease in transition temperature (Tg) and micro-hardness. Raman spectra further showed increase in D1 and D2 peaks corresponding to 3 and 4 member -Si-O-Si- ring structures. Owing to 3 or 4 member rings being more closed pack than usual 6 member rings, this leads to increase in refractive index of glasses post irradiation. Positron annihilation lifetime spectroscopy (PALS) measured an increase in voids/ free volumes in post-irradiated glass. Investigations of the properties post gamma irradiation helped us to better understand the potentials of BaO-PbO-K ₂O-B ₂O ₃-SiO ₂ glasses as radiation shielding windows.