A COMPARISON OF GEL AND GLASS STARTING MATERIALS FOR PHASE EQUILIBRIUM STUDIES

A method of preparing compositions suitable for phase equilibrium studies in systems containing CaO-MgO- Al//2O//3- SiO//2- Fe- O//2- Na//2O employing a gelling technique is described. The subsolidus assemblages obtained from the recrystallization of some of these gels and from the recrystallization of devitrified glasses of the same composition are compared. It is not yet clear whether either starting material has any advantage as the gels may retain early formed metastable phases and the glasses may fail to nucleate stable phases.