Photodegradation mechanisms and pathways for electro-optic polymers

Summary form only given. Although electro-optic polymers can exhibit large electro-optic coefficients which lead to >100 GHz bandwidth devices, their electrooptic effect degrades in time under continuous illumination. Figures of merit for predicting the device lifetimes have been defined and measured for over 40 polymers. Lifetimes varied from a few hours, to almost a year at 1320 nm. To improve photostability, it is necessary to understand the mechanisms (photo-oxidation, cis-trans isomerization, etc.) and number of pathways (in which excited states are involved) in the photodegradation process. Experiments were carried out in different atmospheres for two prototypical polymers DANS (4N,N´-dimethylamino-4´ nitrostilbene) and DR1 (disperse red, 1,4-[N-ethyl-N-(2-hydroxyethyl)amino]-4´-nitroazobenzene). Multiple photodegradation pathways and mechanisms were found.