Study on the influence of TiO2 on the characteristics of multi component modifier oxide based B2O3 glass system

A series of borate glasses mixed with different modifiers (viz., PbO, BaO, CaO, MgO and ZnO of 10 mol% each) and doped with different concentrations of TiO2 (1.0 to 3.0 mol% in the steps of 0.5) was prepared by melt quenching technique. The prepared samples were characterized by XRD, SEM and spectroscopic techniques. The XRD studies have confirmed the amorphous nature of the samples while the SEM pictures revealed the presence of minute fraction of crystallites (of the size <0.1 μm) in the samples. IR spectral studies of the glasses exhibited vibrational bands due to BO3, BO4, BOB, PbO4, ZnO4, TiO4 and TiO6 structural units. The optical absorption and EPR spectral studies have revealed probable presence of Ti3+ ions that act as modifiers and induce structural defects such as dangling bonds, non-bridging oxygens (NBO's) in the glass network. The observed decrease in the optical band gap with increase in the concentration of TiO2 is attributed to the gradual reduction of Ti4+ ions (which participate in the glass network forming) in to Ti3+ ions that act as modifiers.