Thermal Equation
Phenomenological models calculate the structural relaxation of glass forming liquids during non isothermal cooling and heating. The tool narayanaswamy moynihan equation accounts for the dependency of the relaxation time on both the temperature and the current state of the material. It uses the concept of fictive temperature to describe how the material remembers its past thermal history.
Coefficient Structure
Multiple parameters characterize the non linear and non exponential nature of the relaxation process. The tool narayanaswamy moynihan equation includes an activation energy, a partitioning coefficient, a stretching exponent or a reference temperature. These variables allow the model to predict how the glass transition temperature shifts with the cooling rate.
Structural Evolution
Internal state variables represent the structural configuration as if the material were in equilibrium at a different temperature. In the tool narayanaswamy moynihan equation, the fictive temperature evolves toward the actual temperature at a rate determined by the relaxation time. This evolution explains the hysteresis observed in heat capacity measurements during thermal cycling.
Accurate modeling of this shift is necessary for precision glass molding and fiber optic manufacturing.
Optimization Procedure
Optimization routines derive the model constants from experimental calorimetry or dilatometry curves. The tool narayanaswamy moynihan equation provides the best fit when the cooling and heating rates are varied over several orders of magnitude. Consistent parameter sets allow for the prediction of material behavior in long term storage.
