Strontium Oxide-Reinforced Borotellurite Glasses: Synthesis, Structure, and Optical Characteristics and γ-Ray and Neutron Attenuation Capability

This work investigates the significant effects of SrO on the structural, physical, and UV–visible (UV–Vis) characteristics and the γ-ray and neutron shielding ability of samarium sodium borotellurite glasses with the composition (46.5-X)B₂O₃ + 0.5Sm₂O₃ + 15TeO₂ + 18Bi₂O₃ + 20Na₂O + XSrO, where X = 0 (SrO0)–12 (SrO12)% with steps of 3 mol.%, designated as SrOX. The glass samples were prepared via the well-known melt quenching technique. The amorphous nature of the fabricated glasses was confirmed by XRD. The density (ρ) of the SrOX samples increased gradually from 3.73 ± 0.01 g/cm³ to 4.04 ± 0.01 g/cm³. The direct optical gap increased from 2.94 ± 0.01 eV to 2.98 ± 0.01 eV, and the indirect gap increased from 2.74 ± 0.01 eV to 2.95 ± 0.01 eV. Several absorption peaks were found for 4f⁵–4f⁵ electronic transitions from ground manifold ⁶H_5/2 to excited samarium ion manifold states. The free volume (V_f), packing density (P_d), ion concentration (N), polaron radius (r_p), internuclear distance (r_i), field strength (F), molar volume of the boron atoms (V_b), and average boron–boron distance (d_BB) changed significantly as the SrO concentration varied in the glass network. The linear attenuation coefficient (µ) followed the order: SrO0 < SrO3 < SrO6 < SrO9 < SrO12. The synthesized SrO12 glass sample had the lowest half-value layer (HVL). The fast neutron removal cross-section (FCS) values of the SrOX glass samples were 0.085 cm⁻¹, 0.085 cm⁻¹, 0.085 cm⁻¹, 0.086 cm⁻¹, and 0.086 cm⁻¹ for samples SrO0, SrO3, SrO6, SrO9, and SrO12, respectively. The obtained results showed that the proposed compositions can be used in optical applications as well as γ-ray and neutron shielding materials.