The optical absorption and infrared (IR) spectra of mixed alkali silicate glasses in the system 3SiO(2)-(1 -x)Na2O-xK(2)O + 2.5-20 g of TiO2 were measured. Absorption bands due to Ti3+ ions, at 500 and 570 nm, were observed in the spectrum of Na2O-free glasses. The intensities of such bands were followed with the variation in TiO2 content from 2.5 to 20 g (per 100 g of glass). The incorporation of titanium oxide as Ti3+ in the Na2O-free glass, conferring a violet hue to it, was explained on the basis of the acidity-basicity character of the glass, The IR measurements have been used to explore the structural changes throughout the compositional variations.