Bario-titanate borophosphate glasses reinforced Sb₂O₃: fabrication, structure and optical features

Five glasses of composition 53B₂O₃ + 20P₂O₅ + 10BaTiO₃ + (17 − x)Na₂O + xSb₂O₃ where x = 0.0, 1.5, 3.0, 4.5, and 6.0 mol% have been synthesized via the conventional melt quenching technique. The prepared samples coded as SbO-0.0, SbO-1.5, SbO-3.0, SbO-4.5, and SbO-6.0. The structure, physical, and optical properties of the proposed glasses have been investigated. The XRD patterns confirmed that the investigated glasses were in amorphous nature. The density (ρ) of the SbO-glasses increased from3.05 ± 0.01 to 3.34 ± 0.01 g/cm³ and molar volume (V_m) increases as well from32.47 ± 0.01 to 33.75 ± 0.01 cm³/mol for SbO-0.0 to SbO-6.0 samples. FTIR spectra revealed vibrational bands of borophosphate in various spectrum regions. For direct transition, the optical band gap energy (E_g) decreased from 3.93 ± 0.01 to 3.45 ± 0.01 eV, whereas in case of indirect transition, it reduced from 3.61 ± 0.01 to 3.01 ± 0.01 eV. Urbach energy (E_U) values of the investigated glasses increased from 0.26 ± 0.01 for SbO-0.0 to 0.33 ± 0.01 eV for SbO-6.0 sample as the concentration of Sb³⁺ ions increased in the glass networks. The surface (SELF)- and volume (VELF)-energy loss functions were reduced as the amount of Sb³⁺ ions increased. Results indicate that the suggested Sb³⁺ ions doped bario-titanate borophosphate glass samples can be used in the optical applications.