Formation and structural analysis of 15MgO-15CaO-8P2O5-4SiO2 glass

MgO-CaO-P2O5-SiO2 invert glass in the orthophosphate region was successfully prepared using a melt-quenching method, and its structure and dissolution behavior were evaluated. The 31P and 29Si solid-state nuclear magnetic resonance and Raman spectroscopies showed that the glass structure consisted of orthophosphate (Qp0) and orthosilicate (QSi0) tetrahedra cross-linked by cations such as Mg2 + and Ca2 + ions; there were no chain phosphate groups and silicate network structures. MgO present in the glass acts as an intermediate oxide that cross-links Qp0 and QSi0, thereby imparting excellent glass-forming ability. Mg2 + and Ca2 + ions present in the glass were preferentially bonded with silicate and phosphate groups to form SOMg and POCa bonds, respectively. The ions-releasing amount from the glass was higher than that from previously reported phosphate invert glasses.