The previously developed relaxation model for annealing of glass seals with other materials has been applied widely. It remains unclear whether there are a specific low temperature and very long-term iso-thermal treatments at which this simple model ceases to work correctly and requires complication or even revision. With the aim to determine the minimum fictive temperature at which the relaxation model of annealing of glass seal with an elastic material is still applicable, the stresses in the sandwich S52-2 glass-molybdenum seals are measured at different stabilization temperatures. The experimental temperature-time dependences of the stresses are compared with those calculated using the relaxation model of seal annealing. The use of this relatively simple model leads to a quite satisfactory agreement (even if not identical at all the temperatures) in the range from the glass transition temperature to 380${}^\circ$C for stabilization durations as long as 81 days. This treatment duration makes it possible to reach a structural temperature of 434${}^\circ$C, which is considerably lower than the structural temperature (525${}^\circ$C) obtained upon simple cooling of glass at a rate of 3 K/mm.