To evaluate the thermal stability of oxide glasses, various criteria have been used. Not only the simple parameters, as characteristic temperatures and values of activation energy and enthalpy changes, but also the combined criteria E/RTp and kf(T) have been taken into account. Three glasses with the composition of Li2O·2SiO2 (a), Li2O·2SiO2·0.03TiO2 (b) and Li2O·2SiO2·0.1TiO2 (c) were prepared and the validity of the criteria was tested by applying them to these glasses. The results indicate that the sequence thermal stability of the studied glass system vs. crystallization depends not only on their composition but also on the used criteria.