Effect of TiO2 on the structural, thermal and optical properties of BaO-Li2O-diborate glasses

Glasses with a general composition of (30 − x) BaO-xTiO2-70Li2B4O7, where x = 5, 10, 15 and 20, in molar ratio, were prepared by the conventional melt quenching technique. Structural characterizations of the glasses were conducted through FTIR spectrometry and the variation of density values, which allowed the calculation of the glass molar volume (VM). The amorphous nature of the glasses was checked by X-ray diffraction. The compositional dependence of the glass transition (Tg) and crystallization (Tcr) temperatures was determined by differential scanning calorimetry (DSC) analysis. The thermal stability of the glasses increases with an increase of TiO2 content. The optical spectra were measured and the optical band gap was estimated. It was found that the band gap decreases with an increase of TiO2 content. The properties and structural features of glasses were discussed in terms of the relative proportion of former/modifier oxides.