Two new asymmetrical two-photon photopolymerization initiators: Synthesis, characterization and nonlinear optical properties

Two new asymmetrically free-radical two-photon photopolymerization initiators, Diphenyl-{4-[2-(4-pyrrolidin-1-yl-phenyl)-vinyl]-phenyl}-amine (abbreviates to DYVPA) and 9-{4-[2-(4-Pyrrolidin-1-yl-phenyl)-vinyl]-phenyl}-9H-carbazole (abbreviates to PPVPA), have been synthesized and characterized. Linear absorption, one-photon fluorescence emission and their lifetimes, and two-photon fluorescence emission have been investigated. The calculated two-photon absorption cross-sections of DYVPA and PPVPA are 70.1 and 28.0 × 10−50 cm4 s photon−1, respectively. Microfabrications via two-photon initiating polymerization have been studied and the possible photopolymerization mechanism is discussed.