PROPERTIES OF CAO-TIO2-SIO2 GLASSES

Glasses in the system CaO-TiO2-SiO2 with TiO2 content of up to 30 mol% were prepared. The glasses were characterised thermally, chemically a nd mechanically. In all the compositions studied, a strong phase separ ation was observed by transmission electron microscopy, with increased droplet size as the TiO2 content increased. As is to be expected, the thermal expansion coefficients were lower than those of conventional soda-lime glasses. The incorporation of TiO2 into the glass network en hanced microhardness and toughness. The glasses prepared were alkaline resistant and their chemical durability was considerably improved as the percentage of TiO2 increased. A structural study of the incorporat ion of TiO2 in these calcium silicate glasses was carried out by means of infrared spectroscopy. In addition, transition and softening tempe ratures as well as densities, refractive indices and elastic moduli we re determined.