Impact of La₂O₃ Substitution on the Structural, Thermal, and Radiation Shielding Properties of Sodium–Barium Borosilicate Glasses

This study investigates the impact of progressively substituting sodium oxide (Na 2 O) with lanthanum oxide (La 2 O 3 ) in sodium–barium borosilicate glasses with the general formula 60B 2 O 3 –20BaO–10SiO 2 –(10‐m)Na 2 O–mLa 2 O 3 ( m = 0, 2.5, 5, 7.5, and 10 mol%). Structural, thermal, physical, and gamma‐ray shielding properties were comprehensively analyzed to elucidate composition‐structure‐property relationships. X‐ray diffraction and FTIR analyses confirmed significant structural modifications and preserved amorphous characteristics with increased La 2 O 3 content. Thermal analyses demonstrated a marked enhancement in glass transition temperature (from 538°C to 630°C) and crystallization resistance, associated with increased La 2 O 3 content. The 5 mol% La 2 O 3 composition showed the highest thermal stability (Δ T = 234°C). Density increased by 19.4% (3.09–3.69 g/cm 3 ), enhancing radiation shielding performance. Theoretical shielding assessment via the PSD/Phy‐X platform revealed that the mass attenuation coefficients improved by 52% at 0.015 MeV, whereas the half‐value layer decreased by nearly 30% at 15 MeV in the fully substituted glass. These findings demonstrate that La 2 O 3 substitution offers a promising approach for tailoring borosilicate glasses for applications requiring enhanced thermal stability and radiation shielding performance.