Phase separation of borosilicate glass containing phosphorus

Abstract

Sodium borosilicate glasses containing P2O5 and Al2O3 were prepared, and the behavior of phosphorus associated with the phase separation and the effect of Al2O 3 addition have been investigated. After the heat treatment, phase separation by spinodal decomposition was observed in the all samples. In the Al2O3-free glasses, phosphorus was preferentially distributed into B2O3-rich glass phase after the phase separation. With increasing Al2O3 content, the amount of phosphorus distributed into SiO2-rich glass phase increased. According to 31P MAS NMR measurements, in the Al2O 3-containing glasses, Q4 units free from terminal oxygen atoms were formed. It was suggested that the distribution of phosphorus depend on the PO4 units. © 2011 Ceramic Society of Japan.