The enthalpy of crystallization of vitreous sodium-trimetaphosphate is determined and studied versus temperature and time. Isotherm calorimetric studies were performed on glass samples annealed at 310-degrees-C and 320-degrees-c for various times (2 to 24 hours). Using both thermodynamic and crystallographic results (Part I), we proposed and tested a kinetic model for the crystallization of vitreous sodium-trimetaphosphate. This model is in good agreement with experiments.