Synthesis and nonlinear optical properties of two three-branched two-photon polymerization initiators

Two three-branched photopolymerization initiators, 1,3,5-tris[p-(4-N,N-dibutylamino)vinylbenzene]benzene (TBAVBB) and 1,3,5-tris[p-(4-N,N-diphenylamino)vinylbenzene]benzene (TPAVBB) have been synthesized with solid-phase Wittig reaction. The single-photon fluorescence, quantum yields, lifetimes and solvent effects of the initiators were studied in detail, and both compounds were found to exhibit good single-photon fluorescence emission. Two compounds are good two-photon absorptiontive chromophores and operative two-photon photopolymerization initiators. Two-photon absorption (TPA) cross-sections from 730 nm to 870 nm at intervals of 10 nm have been measured with the two-photon-induced fluorescence method, and the maximal TPA cross-sections of TBAVBB and TPAVBB are 432.7 GM and 546.2 GM (1 GM = 1 × 10−50 cm4 s photon−1 molecule−1) at 800 nm, respectively. We measured the quasi two-photon polymerization rates (Rp) based on scanning speed and the width of the written protruding line. Polymerization rates of TBAVBB and TPAVBB were found to be 117.8 μm3 s−1 and 66.2 μm3 s−1 in the case of the laser power 0.3 W at 800 nm, respectively.