Abstract The master sintering curve method was applied to analyze the sintering and crystallization behavior of 15Na 2 O.10CaO.75SiO 2 (SLS) and 17Na 2 O.33CaO.50SiO 2 (NC 2 S 3 ) glasses, in mol %. The densification of samples was successfully analyzed using the master sintering curve (MSC) method; it gives activation energy Q = 310–340 kJ.mol −1, which is in good agreement with the expected activation energy of the viscous flow. While the obtained activation energy enables predicting the sintering behavior of SLS glass, the actual results are different from the estimated data for NC 2 S 3 . The activation energy of crystallization of NC 2 S 3 , determined by constructing Master Kinetic Curves (MKC) was lower than the sintering activation energy: this impairs the prediction ability of MSC for NC 2 S 3 glass.