Amphiphilic dyes for nonlinear optics: Dependence of second harmonic generation on functional group substitution

Communication: Orientation of chromophores by using the Langmuir‐Blodgett film‐prepration procedure, to a degree practically impossible to achieve by poling in polymer matrices in an electric field, has held to materials exhibiting the highest values of the second order susceptibility (χ⁽²⁾) yet known. The effect of different functional groups in both phenylhydrazone and stryrylpyridinium compounds on both molecular nonlinearity and order in the films the factors which most strongly influence (χ⁽²⁾) has been investigated and a thioether substituent is found to increas (χ⁽²⁾) significantly.