ON THE BROADENING OF THE ESR LINE IN PRESENCE OF AIR OR OXYGEN IN CONDUCTING POLYMERS

The oxygen-induced ESR line broadening is investigated in the case of the conducting polymer, polyaniline in the powder form. Pumping under vacuum results in a narrowing of the ESR linewidth from 3.3 to 0.95 Ga uss (full width at half maximum). Subsequent application of air or oxy gen pressures result in a fast broadening to 12 Gauss in both cases. T hen, quite different behaviours are observed. In the case of air, afte r a maximum the linewidth decreases with a time constant of 3 h. This effect gives evidence for different kinetical behaviours for oxygen an d nitrogen. In the case of pure oxygen, a decay of the linewidth is al so observed, but much slower. These effects are reversible.