Impact of Tungsten Oxide Substitution on Structure, Thermal Behavior, and Radiation Shielding in Sodium‐Zinc‐Borate Glasses

A series of sodium‐zinc‐tungsten borate glasses with compositions 20Na 2 O─20ZnO─(60−n)B 2 O 3− nWO 3 (n = 0–20 mol%) were synthesized successfully through a conventional melt‐quenching technique, involving melting at 1250°C. All obtained glass samples (NZBW0–NZBW20) exhibited a purely amorphous structure, confirmed by XRD. Incorporation of WO 3 significantly altered the structural network, decreasing the proportion of BO 4 units, increasing nonbridging oxygens, and forming WO 4 and WO 6 polyhedra. The incorporation of WO 3 resulted in a significant enhancement of density from 2.643 to 3.779 g/cm 3 , while simultaneously decreasing the glass transition temperature from 474°C to 417°C and increasing the coefficient of thermal expansion from 7.85 to 9.36 ppm/°C. Gamma‐ray shielding properties were also significantly improved: at 0.015 MeV, the mass attenuation coefficient increased nearly fourfold (16.7 to 61 cm 2 /g), while the half‐value layer dropped fivefold (0.016 to 0.003 cm) with increasing WO 3 content. These enhancements are attributed to tungsten's high atomic number, demonstrating that WO 3 ‐rich sodium‐zinc‐tungsten borate glasses are excellent candidates for high‐density glass‐based radiation shielding applications.