Immiscibility in the TeO2-B2O3 system

Experimental investigations have been carried out to study the phase separation process in the TeO₂-B₂O₃ system. It was found that the phase diagram is of a eutectic-like type (monotectic invariant reaction), with a wide region of stable and metastable phase separation. During the cooling of the melts two phases are obtained. One has a high TeO₂ content and is a transparent glass. The other, richer in B₂O₃, is opaque and in structure constitutes a complicated microheterogeneous system.