The role of TiO2 in the B2O3–Na2O–PbO–Al2O3 glass system

Optical and vibrational studies have been carried out on 60B2O3·(20−x )Na2O·10PbO·10Al2O3:x TiO2 (x =0, 1, 2, 3, 4, and 5 mol%) glasses, in order to understand the role of TiO2 in the 60B2O3·20Na2O·10PbO·10Al2O3 glass matrix. The X-ray patterns reveal homogeneous glasses over the entire compositional range. The absorption spectra show that the energy of the optical band gap (ΔE opt) and Urbachʹs energy (E U) decreases as TiO2 content increases. The changes observed in the Raman and IR spectra are related to the BO4→BO3 back conversion effect and the appearance of “loose” BO4−BO4− groups. The data indicate that titanium ions act as a network modifier.