Titanium in normal melting conditions in air atmosphere present as Ti 4+ ion in basic silicate glasses exhibited an ultraviolet cutoff in silicate glasses, viz. soda-magnesia-silica, soda-magnesia-limesilica and soda-lime-silica glasses. This indicates that Ti 4+ ion can be a good replacement for Ce 4+ ion in producing UV-absorbing silicate glasses for commercial applications. The wavelength maxima at which the infinite absorption takes place in glasses was found to be around 310 nm against Ti-free blank glass in UV-region. The mechanism of electronic transition from O 2ligands to Ti 4+ ion was suggested as L → → M charge transfer. The low energy tails of the ultraviolet cutoff were found to obey Urbach's rule in the optical range 360-500 nm. The fluorescence spectra of these glasses were also studied and based on the radiative fluorescent properties it was suggested that the soda-lime-silica glass containing Ti 4+ ion with greater emission crosssection would emit a better fluorescence than the corresponding soda-magnesia-lime-silica and sodamagnesia-silica glasses. The shift of emission wavelengths maxima towards longer wavelength in titania introduced silicate glasses was observed on replacement of MgO by CaO which may be attributed due to an increase in basicity of the glass system.

Co 2 • ion was found to produce a variety of colour shades ranging form pinkish blue to intense blue to greenish blue in a series of binary alkali silicate glasses. The optical absorption characteristics of divalent cobalt produce three strong bands in the visible and two weak bands in the near infrared region, respectively in lithium silicate, sodium silicate and potassium silicate glasses. In the present study, the molar extinction coefficients of Co 2 • ion were calculated using Bouger-Beer's equation and the intensities of the bands were reported quantitatively in glasses at their wavelength maxima. The absorption bands in the molar extinction curves for Co 2 • ion were found to shift more towards longer wavelengths with an increase in ionic radius of alkali ion on replacing lithium by sodium and sodium by potassium in glasses. The results were explained with reference to lise and Hartmann equation. Further, the values of molar extinction coefficients were found to increase with Increasing basicity of the alkali silicate glasses as ionic radii of the alkali ions increase in order of K• > Na• > u• in the glass.