1- Color And Optical Properties Of Cao-nao2-sio2 Glasses Containing Low Amounts Of Transition Metal Oxides

The aim of this work is to study the color and optical properties of CaO-Na2O-SiO2glasses containing low amounts of transition metal oxides as TiO2 and Cr2O3.Several compositions were prepared based on Algerian sand (ST). A decrease of thermal expansion coefficients and an increase of glass transition temperatures as TiO2 and Cr2O3content increase were noticed. Optical properties determined by UV-Visible spectroscopy reveal that the glass absorptions decrease with increasing TiO2. Three new absorption bands around 350, 445 and 650 nm characteristic of Cr3+ and Cr6+ ions were also appeared on the spectra of the samples containing Cr2O3. The color parameters (L * a * b * ) showed that the samples with TiO2 were colorless and an improved of clarity was detected. A greenish color and a significant increase in Cr2O3 doped glasses b * parameter values is noticed.