抄録
Systematic measurements by differential thermal analysis have been made on glasses of the system PbO-B2O3, PbO-SiO2, on commercial glasses, borax glass and B2O3 glass. And also the DTA methods have been used for the study of chemical reactions between glass-making materials on the system PbO-SiO2. For all the commercial glasses DTA curves indicate that the transformation phenomena are characteristic and no crystallization takes place.
The transformation range on any glass estimated from the DTA curves coincides exactly with the range measured by the thermal expansion. For the B2O3-PbO and SiO2-PbO glasses the exothermic peaks suggest the formation of borates or silicates, and the endothermic peaks at 600∼800°C suggest the melting of these compounds, and are followed by glass formation. The DTA curves for the batch materials of the system PbO-SiO2 show the endothermic peaks at 720∼760°C or around. These endothermic effects are attributable for 30∼50mol parts PbO-70∼50mol parts SiO2 to the formation of PbO-SiO2, and for 70mol parts PbO-30mol parts SiO2 to the formation of 2PbO-SiO2, 4PbO-SiO2 and the melting of these compounds.
