Morphology and Stability of the Glass Phase in Glass Ceramic Systems

An explanation is given for the apparent stability of a minor phase in a two-phase system, such as a glass in a glass ceramic, even though normally the glass would be expected to dissolve completely into the crystalline phase. It is shown that the glass would be stable only if it is segregated to the triple-junction nodes and only if the dihedral angle is <π/3. The size and morphology of the glass pocket are obtained in terms of the interface energies, the undercooling below the solidus temperature, and the dihedral angle.