Study of third-order nonlinear susceptibility of polySchiff base containing triphenylamine

PolySchiff base containing triphenylamine has been synthesized by polycondensation and characterized by FT-IR, NMR, UV-visible spectrometer. Measurements of the third-order optical nonlinear susceptibility χ(3) by Z-scan technique have shown that the large nonlinearity is dominated by the two-photon absorption in PSB. The sign and size of real part Reχ(3), nonlinear refractive index n2 have been measured with the condition of 532 nm, 8 ns-duration pulses to be −1.23×10−10 esu, −3.06×10−12 esu; nonlinear absorption index β and size of image part lmχ(3) to be 3.63×10−10 m/W, 1.15×10−11 esu, respectively, so the third-order nonlinear susceptibility χ(3) is 1.19×10−11 esu. The value is larger than other polymers reported. PSB is self-focusing material and has potential application in nonlinear optic field.