Figure 1: Structure of polymer PPE
Different mechanisms have been proposed for the initial photochemical step. These can be grouped in two classes.
In this contribution we will present theoretical and experimental studies which will give further insight into the photodegradation mechansims. The low temperature absorption spectra of model compounds allow a decision between intra- and intermolecular mechanisms. The relevance of the proposed intramolecular mechanisms, was studied using semiempirical calculations.