Towards highly transparent tungsten zinc sodium borate glasses for radiation shielding purposes

The impact of tungsten oxide (WO₃) additions on the structure, some physical and radiation shielding parameters of sodium zinc borate glasses have been scrutinized. These glasses were properly produced by the melt quenching method. The amorphous state was affirmed by X-ray diffraction (XRD) data. The internal structure within the short-range order of the glassy network was studied by the method of infrared spectroscopy (IR). The results of IR showed that the BO₄ units are transformed to BO₃ accompanied by the formation of nonbridging oxygens with further WO₃ doping. This transformation of BO₄ to BO₃ and nonbridging oxygens is employed to explain the increase in the molar volume values with changing WO₃/ZnO amount. Further, the optical transmittance was measured within the visible range to assure the transparency of the prepared glasses. The transmittance results confirm the absence of W⁵⁺, W⁴⁺, W³⁺ states; based on the absence of their absorption bands. Also, the transmittance results indicate that the only oxidation state in the present glasses is hexavalent tungsten (W⁶⁺). Additionally, the parameters of radiation protection of the manufactured glasses were investigated. It was found that, the addition of WO₃ improves not only the radiation protection parameters (such as the linear attenuation coefficient) but also the transparency of the prepared glasses. Finally, we concluded that, the addition of WO₃ to the glass samples leads to transparent glasses with an improved shielding ability at low energies but effects slightly at high energies. Due to the high transparency and the increased values of the linear attenuation coefficient of the prepared glasses, they are considered promising glasses in the field of nuclear radiation protection, especially at low energies.