The modern concepts of the structural evolution of glasses take into consideration the nano- and microheterogeneities in them. In the present work, an attempt is made to compare the inhomogeneities in glasses and glass-crystalline materials in the systems GeO2-TeO2-B2O3 and GeO2-TeO2-V2O5. Using transmission electron microscopy, scanning electron microscopy and energy dispersive x-ray analysis in the three component samples a large variety of nano- and micro-scale heterogeneous formations is observed: droplet-like structures, interconnected and multiple separated phases, complex aggregates of amorphous or crystalline origin. The presence of this abundance of inhomogeneities arises from different reasons. The existence of regions of stable and metastable phase separation in the boundary binary systems TeO2-B2O3 and GeO2-TeO2.
