Synthesis and optical properties of NLO chromophores containing an indoline donor and azo linker

A suite of new nonlinear optical chromophores containing an indoline donor and azo linker has been synthesized in high yields. The methodology used allows for the incorporation of various acceptor systems, the ready isolation of the target compounds and access to materials with excellent thermal stabilities (viz = Td 220–270 °C). The first hyperpolarizabilities of the compounds were measured by hyper-Raleigh scattering and all were found to have an excellent response. The highest value measured was 1640 × 10−30 esu in DMF at 800 nm for a chromophore containing the well-known TCF acceptor system. Based on data obtained in this and other studies, there is evidence that chromophores containing indoline donors are capable of providing compounds with molecular NLO responses higher than those containing donors derived from N,N-disubstituted anilines.

► We have prepared a new series of NLO chromophores with indoline donors and azo linkers.
► The methodology allows for the facile synthesis of the target molecules in high yield.
► The compounds have high first hyperpolarizabilities with values of up to 1640 × 10−30 esu found.
► The compounds are also thermally stable and have decomposition temperatures of over 250 °C.
► The results suggest that donors based on indoline may be better than those based on aniline.