Effects of BaO on the glass formation of the PbO-B2O3-TiO2-BaO system in relation to transition temperatures

The variation of the BaO content on the quaternary PbO-B2O3-TiO2-BaO system's glass formation tendency was investigated in relation to transition temperatures, such as melt temperature (T-f), liquidus temperature (T-l), crystallization temperature (T-c) and glass transition temperature (T-g). Compositions were melted between 800degreesC and 1300degreesC. In order to obtain bulk glass samples, glass formation was carried out using a preheated cylindrical brass mould without forcing the cooling rate to increase. Glass formation tendency increased with increasing the temperature ratios of T-g/T-l and T-c/T-l and with decreasing T-g/T-c. Eutectic compositions preferentially formed glasses from melts due to their low melting temperatures. (C) 2002 Kluwer Academic Publishers.