Two novel fluorinated poly(arylene ether)s with pendant chromophores for second-order nonlinear optical application

Two fluorinated poly(arylene ether)s, P1 and P2, containing perfluorophenyl moieties in the main chains and second-order nonlinear optical (NLO) chromophores in the side chains have been conveniently prepared by Knoevenagel condensation reaction between perfluorophenyl-containing poly(arylene ether) P and cyanoacetylated NLO chromophores 2 and 3 for the first time. The molar percentages of the pendant chromophores were estimated to be 162% and 138% for P1 and P2, respectively, and their weight percentages were both 42.3%. Both of the two polymers are thermally stable and readily soluble in common organic solvents. The glass transition temperatures (T-g's) of P1 and P2 were determined to be 186 and 192 degreesC, respectively. The in-situ second harmonic generation (SHG) measurement revealed the resonant NLO coefficient (d(33)) values of 60 and 31 pm/V for the poled films of P1 and P2, respectively. The thermal stability of the SHG signals of the polymer films was studied by the depoling experiment in air using P1 as the typical polymer, in which the decay onset of the SHG signal occurred at around 160 degreesC.