The Effect of TiO2 on the Optical and Mechanical Properties of Heavy Metal Oxide Borosilicate Glasses

The density, the molar volume, the rigidity, the UV reflectance and the glass transition temperatures of the x TiO2 - 20Na(2)B(4)O(7) - 30PbO - 20SiO(2) - (30-x) Bi2O3 glass system were determined. These physical parameters were acquired by using the DTA, ultrasonic and UV techniques to explore the effect of TiO2. The replacement of Bi2O3 by TiO2 decreased these physical parameters, which suggested the glass modifier role of TiO2. This attitude can be attributed to the smaller ionic radii, the density and the polarizability of TiO2 than that of Bi2O3. Moreover, according to the FTIR, TiO2 created non-bridging oxygens in the network that decreased the bond strength of the glass system. The decreases of the rigidity, the glass transition temperature and the optical band gap are sensitive to the decrease of the bond strength and the created non-bridging oxygens in the lead alkali borosilicate network. The obtained results were discussed in relation to the role of TiO2 in the lead borosilicate glass system.