Effect of PbO, Bi2O3 and Tl2O on Optical Properties of Heavy Metal Gallate Glasses

The effects of composition on refractive index, density, glass transition temperature, and ultaviolet-visible and infrared transmissions were studied for gallate glasses containing a large amount (80mol%) of PbO, Bi2O3 and Tl2O. The resonance wavelengths of Pb2+, Bi3+ and Tl+ were determined from the reflection spectra of gallate glasses. The refractive indexes of gallate glasses were measured down to the fourth decimal in the wavelength range of 480nm to 1710nm using the minimum deviation method. Refractive index in the system Bi2O3-PbO-Ga2O3 increases as PbO is substituted for Bi2O3. Refractive index in the systems Tl2O-PbO-Ga2O3 and Tl2O-Bi2O3-Ga2O3 increases as Tl2O content increases. Factors affecting the refractive index of heavy metal gallate glasses are discussed by using the single-oscillator Drude-Voigt equation.