Mechanical properties of mixed modified oxide glasses

Mixed modifier effect refers to the nonlinear variations of glass properties when mixing different types of modifier ions. The effect plays an important role since it can be applied to design glasses with controlled properties and it is also related to the raw materials selection. In this review, we will summarize the recent important progress on the mixed modifier effect in oxide glasses. The effect has been found in various properties, but we mainly focus on glass transition temperature (T_g), hardness (H), elastic modulus (E), and coefficient of thermal expansion (α) since these properties are critical in glass manufacture and products performance. Different properties exhibit unique features and many theories are proposed to account for the effect. The compositional dependence of these properties is reviewed and the theories proposed to explain this effect are discussed. Moreover, we suggest some future directions for the further work on the mixed modifier effect.