Push-pull benzoxazole based stilbenes as new promising electrooptics materials

Photoinduced linear electrooptics effect (EOE) was discovered for three push-pull benzoxazole based stilbenes with different electron withdrawing and donating substituents at the phenylene and methane groups. The ground state geometry optimization for trans-stilbene has been performed using molecular mechanic geometry optimization within a framework of MM + force field method. We have done simulations of the optical absorption spectra and we have compared them with the experimental spectra. Quantum chemical simulations of UV-absorption spectra were done within a framework of semi-empirical restricted Hartree-Fock level (RHF) by AM1 (Austin Model 1) and PM3 (Parametric Method 3) methods. In addition, semi-empirical quantum mechanical calculations were carried out to verify reliability of theoretical simulations with respect to experimental data. Furthermore, semi-empirical quantum mechanical calculations indicated substantial difference of absorption obtained for the stilbenes possessing the in-plane and out-of-plane benzoate complexes. The maximally achieved value of photoinduced EOE coefficient was equal to 11.7 pm/V during illumination by lambda = 1060 nm and lambda = 530 nm coherent wavelengths. Correlation between the AFM morphological structure and EOE coefficients for the three investigated stilbenes was demonstrated.