Structural and optical properties of BaTiO3 modified cadmium alkali borate glasses

Borate glasses Na2B4O7-CdO-CuO-BaTiO3 have been manufactured by the traditional melt quenching method. The increment of BaTiO3 affects strictly the density and the molar volume of the glass samples. The spectroscopic investigations by FTIR and Raman spectra show that the glass network consists of different structural units of [BO3] and [BO4] along with [TiO4]. The elaborated investigations assume the glass former role of TiO2. These arguments depend on the transformation of [BO3] into [BO4] units, which result in a decrement in the magnitude of disorder in the glass structure. The compositional dependence on BaTiO3 reveals that the behavior of Urbach energy confirms the increment of the disorder and the trend of the optical band gap shows a decrement process with a priority to direct transitions. Moreover, EPR spectra revealed that the Cu2+ ions occupy the positions of elongated octahedral positions with tetragonal distortions.