Click modification of azo-containing polyurethanes through polymer reaction: Convenient, adjustable structure and enhanced nonlinear optical properties

Eight novel polyurethanes with adjustable structures were prepared from two basic polymers; the compounds displayed good solubility in common organic solvents and high thermal stability. The presence of terminal alkyne moieties further improved the thermal stability of the polymers. The resonant d33 values of the polymers could be improved up to 1.55 times by attaching suitable isolation spacers, with the achieved highest d33 value to be 94.4 pm/V.