Preparation of functional glasses and glass ceramics using stable immiscibility

High functionalization of materials by the combination of heterogeneous substances has become an important procedure for the development of high-performance materials. In various procedures for composite processes, the phase separation of glasses has a potential for use with combinations of the varieties of functional materials spontaneously in nanometer and micrometer scale. Moreover, because phase separation is applicable not only to glass-glass combinations but also to glass-crystal combinations which can control both crystalline phase and inside structure of the composite simultaneously, the utilization of phase separation becomes an interesting and effective technique to create novel high-performance composite materials. In this review, the phase separation of inorganic glasses and glass ceramics mainly caused by stable immiscibility phenomena in high-temperature melts and their applications to the preparation of the high-performance composites are summarized. The preparation procedures and the performances of the materials in silicate systems were described specifically, centering on the studies of the author's group such as luminous, magnetic, and photocatalytic materials.