EPR study of the cis-trans isomerization process in polyacetylene films

Abstract
Using EPR we have studied the isomerization process converting cis-(CH) x films to the trans form upon thermal treatment. Following the measured linewidth and number of spins versus time and temperature, it is shown that for the lowest temperatures (T < ∼ 140 °C) isomerization cannot be complete while for the highest ones (T > ∼ 200 °C) degradation becomes more and more efficient. There exists a small temperature range ( T ∼ 140-150 °C) where optimal characteristics (total isomerization + small degradation) can be achieved