Continuation of the investigation of dielectric properties under a superimposed d.c. stress

Over the superimposed d.c. stress range of 0.04 to 40.0 V/mil, loss tangents are reduced by increasing d.c. stresses in almost a uniform manner. That d.c. and a.c. conductances are equivalent at the high stress levels only, indicates that the loss tangents measured at such superimposed d.c. stresses are indicative of the true state of polarization effected by the d.c. stress. Under such conditions, ε´ remains unaffected. Both a.c, and d.c conductance activation energies agree essentially with that for viscous flow. The d.c. current-voltage relationships are in agreement with what has been noted in the recent literature for a similar chemical system and can be interpreted, at least partially, on a theoretical basis.