The conductivity was measured by using complex impedance methods at frequencies of between 5Hz and 500kHz, and at temperatures of between -20 and 90C. An Arrhenius plot revealed a change in slope near to 30C, and 2 activation energies were deduced (2.01kcal/mol below 30C and 1.76kcal/mol above 30C).

C.Garcia, J.I.Franco, J.C.Lopez Tonazzi, N.E.Walsöe de Reca: Solid State Ionics, 1983, 9-10, 1233-6