Frequency dependence of activation energy () in different temperature ranges (50–380°C, 380–420°C, 420–520°C, 540–565°C, 565–655°C, and 675–700°C). Value of calculated using the Arrhenius relation , where is the pre-exponential factor, is the Boltzmann constant that equals 8.617343 × 10−5 eV·K−1 and is the temperature in Kelvin.
