NLO‐polymers containing tert‐butyloxycarbonyl protecting groups: Modification after processing leading to thermally stable nonlinear optical materials

A new polymer for nonlinear optics (NLO) based on male‐imide/methylvinyliscocyanate precursor polymers is introduced. This side‐chain copolymer is cured after spin‐coating and before poling, which, by a thermally activated fragmentation reaction, leads to increased glass transition temperature, increased density of NLO chromophores, and reduced solubility. NLO materials will play an important role in optical telecommunications, but the problem of the chromophores relaxing back into the isotropic state must first be solved.