Structural, Physical, and Optical Characteristics and γ-Ray Protection Efficacy of Fluoroboro-Tellurite Glasses Reinforced with La³⁺ Ions

Fluoroboro tellurite glasses containing La₂O₃ with nominal composition of 43B₂O₃ + 33TeO₂ + (12−x)BaF₂ + 12Na₂O + xLa₂O₃ x = 0 (La0.0), 0.5 (La0.5), 1 (La1.0), 2 (La2.0), and 3 (La3.0) mol% were fabricated using the melt quenching technique. The effects of La³⁺ ion content inclusion in the prepared glass matrices, including the structural, physical, and optical properties and γ-ray protection efficacy, were then explored. The amorphous state of the La-glasses was verified by the broad and diffuse dispersion of all XRD patterns at low angles. As La₂O₃ additives were added from 0 to 3 mol%, the density (ρ) increased from 3.6243 g/cm³ to3.8743 g/cm³ and the molar volume (V_m) decreased from 30.6488 cm³/mol to 29.8364 cm³/mol. Lanthanum ion concentrations (N_La) increased from 0 for La0.0 glasses to 312.1103 × 10²⁰ cm⁻³ for La3.0 glasses. The polar radius decreased from 0 Å to 3.7813 Å, whereas the ligand field strength between La ions and their surroundings increased from 0 Å⁻² to 18.1839 Å⁻². Values of optical gap (E_g) varied from 3.07 eV to 2.82 eV. The values of linear refractive index (n₀) varied from 2.383 to 2.443, whereas values of nonlinear refractive index (n₂) changed from 5.16 × 10⁻¹¹ esu to 6.40 × 10⁻¹¹ esu for La0.0 and La3.0 glass specimens. Mass (MAC) and linear (LAC) attenuation coefficients were lowest in La0.0 glasses and highest in La3.0 glasses. The trend of the mean free path (MFP) of La-glasses was inverse to that of the LAC and MAC. The order of the MFP trend, which indicates the influence of La₂O₃ in the glass matrix, was typically (MFP)_La0.0 > (MFP)_La0.5 > (MFP)_La1.0 > (MFP)_La2.0 > (MFP)_La3.0. Results show that the recommended glasses appear to be promising materials for various optical devices and radiation protection applications.