Mixed-modifier effect in (Ca,Mg) metaphosphate glasses

The effect of modifier mixing on structure and properties of (Ca, Mg) metaphosphate glasses is considered across the binary join of xMgO-(1-x)CaO-P2O5. Pronounced extrema in hardness, Young's modulus, local creep and glass transition temperature are related to variations in modifier precipitation. Both alkaline earth species compete for octahedral lattice sites, what leads to an increase in the fraction of [MgO4] tetrahedral units at equimolar mixing. At the same time, the structural backbone of phosphate Q2 species is affected through favorable formation of ring- and chain-like superstructures in the presence of Ca2 + and Mg2 +, respectively.