  We obtain the frequency and temperature dependence of the conductivity for
(disordered) solids, where the temperature dependence is defined in terms of
the related thermodynamic state function in exponential (or power law, etc.)
forms. The model is applied to n-type Si with various donor and acceptor
impurities and several concentrations at T about 0 Kelvin and sodium borate
glasses and mixed alkalis with various compositions (x) in all at T about 500
Kelvin. The results are found in good agreement with experiments.
