Investigation on structural, optical, thermal and gamma photon shielding properties of zinc and barium doped fluorotellurite glasses

Fluorotellurite glasses based on zinc and barium fluorides with total dopant concentration limited to 40 mol% in tellurite glass matrix were obtained by melt quenching technique. Explicit effects of both the zinc and barium fluorides on the tellurite glass network were observed from their response to various studies. The tendency of fluorine atoms to break the network was observed from the formation of more non-bridging sites instead of bridging sites from Raman measurements. Formation of these non-bridging fluorine sites instead of non-bridging oxygen led to an increase in the optical band gap of these samples from 3.36 eV to 3.52 eV. The reduction in the glass transition temperature from 316 degrees C to 299 degrees C observed with zinc fluoride doping is due to the breakage in the rigid network structure, while the increase from 316 degrees C to 329 degrees C with barium fluoride doping is correlated to the effect of size of barium atoms in the network. Radiation shielding properties calculated in terms of parameters like mean free path, mass attenuation coefficient etc., showed that the presence of more heavily doped elements like barium in the glass matrix led them to exhibit better shielding properties which can be utilized as replacement materials for concrete and lead based glasses as efficient shielding materials.