Thermal properties, density and structure of percalcic and peraluminus CaO-Al2O3-SiO2 glasses

Calcium silicate and aluminosilicate glasses with various SiO2 contents (10-76 mol%) were prepared in the wide range of [Al2O3]/[CaO] molar ratio from 0.10 to 4.00 by conventional melt-quenching method and an aerodynamic levitation device for a part of peraluminus glasses. Variations of glass transition temperature, the coefficient of linear expansion, and ionic packing factor derived from density measurements with [Al2O3]/[CaO] molar ratio were studied. The glass structures of SiO4 three dimensional network, mixed anions of (Si, Al)O4 tetrahedra, isolated AlO4 and Al-O-Al linkages were evaluated by FT-IR measurements. Compositional dependences of the properties are qualitatively related to the glass structure examined by IR spectroscopy and the proportions of AlOx (x = 4, 5, 6) species evaluated in a previous study by using 27Al MQ NMR spectroscopy.