Synthesis and nonlinear optical properties of donor-acceptor dyes based on triphenylpyrazolines as a donor block and dicyanoisophorone as acceptor

A series of donor-acceptor dyes based on polyfluoro-substituted triarylpyrazolines (as a donor block) and a dicyanoisophorone group (as an acceptor) were synthesized using the Knoevenagel condensation. The dyes have an absorption in the region of 509-514 nm and intense luminescence at 648-663 nm in chloroform with a large Stokes shift (up to 4410 cm(-1)). Based on the synthesized dyes, chromophore-polymer (guest-host) films were obtained in a polycarbonate matrix with a chromophore content up to 27 wt.%. Poling of chromophore-polymer films was carried out in an electric field of a corona discharge and the coefficient of nonlinear optical response d(33) was measured by the second-harmonic generation method of the fundamental frequency of a Nd-YAG laser (1064 nm). The obtained films have a high initial thermal stability and a nonlinear optical response up to 80 pm V-1, which persists up to 115 degrees C.