New nonlinear optical polyamides: Influence of binding mode of side-chains and rigidity of main-chains on temporal stability

New nonlinear optical rigid polyamides were synthesized and the influence of the binding mode between nonlinear optical chromophores and oxybutyl spacers, as well as of the rigidity of the main-chain on the second-order nonlinearity were investigated. The polyamides with side-on binding mode exhibit higher temporal stability of the polar order than analogous polyamide with end-on binding mode. By decreasing the rigidity of the main-chain of side-on polyamides, polyamide with 4,4'-methylenedianiline reveals enhanced solubility and processability, still keeping a high temporal stability compared to the relatively rigid polyamide with 1,4-phenylenediamine.