Equation describing the enthalpy relaxation, \(\Delta H\) which is observed during the annealing of polymers in the glassy state at a temperature, \(T_{\rm{a}}\), lower than \(T_{\rm{g}}\) \[\Delta H(t_{\rm{a}}) = \Delta c_{p}(T_{\rm{g}} - T_{\rm{a}}) \exp\!\left[- \left (\frac{t_{\rm{a}}}{\tau} \right)^{\beta} \right]\] \(\Delta H\) = difference of the enthalpy in the initial, glassy state, and the enthalpy of the glassy state after annealing; \(t_{\rm{a}}\) = time of annealing; \(\Delta c_{p}\) = difference in heat capacity at the glass-transition temperature, \(T_{\rm{g}}\), and the starting temperature of the annealing process, \(T_{\rm{a}}\); \(\tau\) = relaxation time at \(T_{\rm{a}}\); \(\beta\) = exponential factor.