Effects of La₂O₃ on structure and mechanical properties of sodium borosilicate glass

To develop rare-earth-doped borosilicate glasses with enhanced mechanical properties, lanthanum sodium borosilicate glasses were successfully synthesized using a fusion method. The glass composition was (mol.%): 55SiO₂ - 25B₂O₃ – (20-x)Na₂O - xLa₂O₃ (x = 1, 2, 3, 4, and 5). The primary aim was to investigate the impact of Na₂O substitution by La₂O₃ on the structural and mechanical characteristics of the glasses. X-ray diffraction analysis confirmed the amorphous nature of the samples, while Raman and Fourier-transform infrared spectroscopy indicated a conversion of BO₃ to BO₄ units. Additionally, differential thermal analysis revealed an increase in both glass transition and crystallization temperatures with higher La₂O₃ content. The inclusion of La₂O₃ enhanced the glass density, Vickers hardness, fracture toughness, and Young's modulus, owing to the larger ionic radius of La³⁺ compared to other components. In summary, the incorporation of an optimal concentration of La₂O₃ significantly improves the mechanical properties of these sodium borosilicate glasses, making them more suitable for applications involving the containment of actinides in nuclear fuel reprocessing.