Thermal properties of rubidium and cesium borosilicate glasses have been found to depend on the ratio of main components. The values of glass transition temperature and crystallization temperature have been determined, as well as the peculiarities of crystallization process at various heat treatment conditions. The fraction of crystallized phases have been found, in two samples the phase type have been determined. It has been shown that crystallization processes are especially pronounced in rubidium glasses. The obtained values of glass transition and crystallization temperatures make it possible to determine the values of heat treatment parameters for glass-containing nuclear waste matrix materials depending on the ratio of the main components.