STRUCTURE, GLASS STABILITY AND RHEOLOGICAL PROPERTIES OF Na2O-CaO-Al2O3-SiO2 GLASSES DOPED WITH Y2O3

The structure, glass stability and rheological properties of Na2O-CaO-Al2O3-SiO2 glasses with different Y2O content have been invesigated by DSC, FTIR, rotating crucible viscometer and dilatometry. The results showed that the addition of Y2O3 reduced the polymerization degree of glass network, but made the glass structure more compact. The coefficient of thermal expansion, density and glass transition temperature increased with the increase of Y2O3 content. The crystallization peak temperature and glass stability decreased firstly and then increased. While the melting temperature and forming temperature showed the opposite trend. The working temperature and Littleton softening point went up gradually. As the Y2O3 content changing from 0 to 2 mol. %, the fragility index m decreased firstly and then increased, while the glasses working temperature range AT experienced an opposite change.