Synthesis and optical properties of poly[2-{N-Methyl-N-(4-(4- ethynylphenylazo)phenyl)amino} ethyl butyrate]

The high-molecular-weight functional polyacetylene that contain a para-aminoazobenzene chromophore, poly[2-{N-Methyl-N-(4-(4-ethynylphenylazo) phenyl)amino}ethyl butyrate] [poly(EAPAB)}, was synthesized in moderate yield and characterized by FT-IR, ¹H NMR, UV-vis, TGA, and GPC. The nonlinear optical and optical limiting properties were performed with 8 ns pulse width at 532 nm wavelength. The results show that the introduction of the flexible amino group effectively improved the solubility of polymer [poly(EAPAB)] in common oiganic solvent, such as CHCl₃, THF, and dioxane, while poly(4-ethynylazobenzene) [poly(4EAB)] without the flexible amino group shows poor solubility in common organic solvent. Simultaneously, poly(EAPAB) still shows good thermal stability, large third-order nonlinear optical property, and novel optical limiting property owing to the functionalization of the para-aminoazobenzene chromophore.