Substitution of Li+, Mg2+, Sr2+, Ba2+ and Zn2+ for 50 or 100% of Na+ in glass with composition 3Na2O·7P2O5·10SiO2 resulted in liquid immiscibility in some of the new glasses. Glasses containing SrO and BaO were studied more thoroughly, and a high-silica porous glass was obtained from 3SrO·7P2O5·10SiO2 glass by heat treatment at 500 to 700° C and subsequent leaching with 3N HCl. However, this porous glass proved incapable of sintering into a bulk glassy body, because of its high rate of cystallization.