Effect of BaTiO3 on the structural and optical properties of lithium borate glasses

The conventional melt quenching technique was used to fabricate the glass samples with addition of barium titanate (BT) into (70B2O3–29Li2O–1Dy2O3) glass matrix. The glassy nature of the samples was confirmed from X-ray diffraction studies. Increase in density and the decrease in molar volume of the glass samples indicated the compactness of glass network upon addition of BT. FTIR studies revealed the progressive conversion of trigonal BO3 units into tetrahedral BO4 structural units with increasing BT content. The Raman spectra illustrated a remarkable shifting of Raman scattering peaks to the lower/higher wavenumber as the concentration of BT is increased. DSC studies were carried out on the samples to determine their glass transition and crystallization temperatures. The study of the optical data obtained from the prepared samples showed a decrease in both the indirect and direct optical band gap energies with an increase in BT content. The influence of the BT addition on molar refractivity, molar polarizability and metallization criterion has also been studied and the values of metallizatin criterion suggest the applications of these glasses in nonlinear optical devices.