An alternative synthetic route to soluble polyetherimide derivatives with high second‐order optical nonlinearity

Abstract
Processible polytherimide‐based polymers that display nonlinear optical (NLO) activityare reported to have been synthesized by the Mitsunobu reaction, in which the polyimide structure is synthesized directly in a single step from a diimide and a diol, without a high‐temperature thermal imidization step. The resulting polymers, with pendant‐incorporated tricyanovinyl azobenzene chromophores, showed very large second‐order NLO activity with good temporal and thermal stability—in one case no decay of the signal was observed up to 125°C.