Guest-host interaction of some aminoazobenzene dyes doped in liquid crystalline matrix

The polarized spectroscopy of three aminoazobenzene dyes with various molecular size and alkyl tails were obtained in a nematic matrix and the dichroic ratios R and order parameters S of the dyes were determined by measuring the intensity of the absorption bands in the visible region of parallel aligned samples. The interaction of these dyes with the anisotropic surrounding and with those of the isotropic organic solvents was investigated and compared. The electronic absorption spectra of the dyes in the anisotropic matrix were red shifted as compared to the isotropic organic solutions, indicating strong molecular interactions between the dye molecules and liquid crystalline matrix. The electro-optical effects of the guest-host systems were also investigated using polarized spectroscopic method.