Surface Tension and Density of Molten Borosilicate Glass Measured by Sessile Drop Method

In the present research, surface tension and density of borosilicate melts were measured and compared to that of Na-Ca containing glass melt using sessile drop method. The results show that the density of borosilicate melt, always lower than that of Na-Ca containing glass melt, decreases linearly with temperature rising. The temperature dependence of density indicates a lower thermal expansion coefficient of borosilicate melt. The surface tension of both borosilicate and Na-Ca containing glass melts increases linearly with temperature within 1000 degrees C similar to 1200 degrees C and temperature coefficients are 0.27867 and 0.11867, respectively. It is reasonable to deduce that higher surface tension and temperature coefficient of borosilicate melt are attributed to the effect of boron oxide.