EFFECT OF ALUMINIUM IONS ON COVALENT BEHAVIOUR OF <font>Li2CO3-B2O3</font> GLASSES

The paper undertakes the preparation of Aluminium oxide doped Lithium borate glasses and characterizes to investigate the physical and optical studies of these glasses using density and UV-Visible spectroscopy. Results had been obtained with the help of FTIR Spectra in our previous work which indicate that Al2O3 acts as a network modifier by converting three coordinated boron atoms [ BO3 ] to four coordinated boron atoms [ BO4 ]. The effect of aluminium content on the optical properties of the present glass system has been studied from the optical absorption spectra. It shows the shifting of the band edge towards the higher wavelength and that there is corresponding decrease in the band gap, which is due to the conversion of BO3 to BO4 units. The evaluation of the compact structure of prepared glass samples with the presence of [ BO4 ] groups has been made in terms of the physical properties such as density and molar volume. It is also confirmed by average boron-boron separation results. The research findings confirm that the addition of Aluminium oxide increases the covalent value and corresponding decrease in ionicity behaviour.