Synthesis of new type of nonlinear optical chromophores: The introduction of a novel aromatic amine donor 1-oxajulolidine to enhance the electro-optical activity of organic second-order nonlinear optical materials

Developing new organic second-order nonlinear optical chromophores with a new electron donor is crucial for enhancing performance of electro-optic (EO) materials. A series of new second-order nonlinear optical chro-mophores (J1, JS and JO) with new electron donor 1-Oxajulolidine have been designed and synthesized. Ref1, Ref2 and Ref3 with N, N-diethylaniline (DEA), 4-anisole and julolidine as electron donor had also been syn-thesized for comparison. The result of TGA and DSC tests suggested that the decomposition temperature of the chromophores was higher than 260 degrees C. As the UV-vis absorption spectra of chromophores in solution, maximum absorption (lambda max) of the chromophores J1 with 1-Oxajulolidine group presented red-shift compared to Ref1 and Ref2, but blue-shift to Ref3. Nevertheless, chromophore with 1-Oxajulolidine presented more obvious sol-vatochromic behavior from dioxane to dichloromethane. Density functional theory had been used to calculate HOMO-LUMO energy gaps and beta of these chromophores. The r33 values of guest-host EO polymers Ref1/APC, J1/APC, JS/APC and JO/APC with a loading density of 10 wt% were obtained as 7.5, 9.6, 15.3 and 13.5 pm V-1, respectively. The above result clearly indicated that r33 of J1/APC (9.6 pm V-1) was 27% higher than that of Ref1/APC (7.5 pm V-1). The electro-optic coefficient of JS with the same conjugate bridge and acceptor was higher than that of FTC in the same doping concentration. As revealed by the above results, the introduction of the polycyclic structure of 1-Oxajulolidine, containing two electron-rich atoms (N and O), could efficiently enhance the electro-optical performance. Furthermore, lambda max of JS in doped film showed blue-shift compared with FTC which exhibited a promising potential for tackling nonlinearity and transparency trade-off in second-order nonlinear optical (NLO) materials.

Automated summary

Developing new organic chromophores with a new electron donor is crucial for enhancing the performance of electro-optic materials. In this study, a series of new chromophores with 1-Oxajulolidine as the electron donor were designed and synthesized, and their properties were investigated. The results showed that these chromophores exhibited improved performance, indicating their potential applications.