Optical Properties and Structure of BaO-TiO2-SiO2 Glass Ceramics

Nanocrystallized glasses with the composition of (50-x)BaO-xTiO(2)-50SiO(2) (x = 10, 15, 16.7 and 20) have been prepared by heat-treatment at T. (crystallization onset temperature) for 3 h, and their optical properties, photoluminescence (PL), XRD and Raman spectra have been examined. The absorption edges of the glasses were red-shifted and the absorption coefficient increased with an increase of TiO2. The glass subjected to the heat-treatment showed a dense formation of Ba2TiSi2O8 crystals. The XRD and Raman results show that the nanocrystallized glasses formed fresnoite phase up to TiO2 concentrations of 15 mol%. Furthermore, blue luminescence with a peak at the wavelength of around 470 nm was observed in the nanocrystallized glass, demonstrating the optical multifunctional nanocrystallized material such as non-linear optics and photo-luminescence. It is thought that the blue luminescence from the BaTiSi2O8 nanocrystallized glass originated from the presence of Ti4+ incorporated into the fresnoite-type structure.