FERROELECTRIC LIQUID-CRYSTALLINE POLYSILOXANES DESIGNED FOR HIGH 2ND-ORDER NONLINEAR SUSCEPTIBILITIES

Ferroelectric liquid crystalline (FLC) copolysiloxanes containing suit able comonomers (''NLO-chromophores'') for second harmonic generation (SHG) have been prepared. Their important feature is a donor-acceptor pi-system sited perpendicular to the long axis of the side-group moiet ies in order to adopt the polar ordering of the ferroelectric LC phase . The influcences of the mesogen structure and of the content of NLO-c hromophores on the liquid crystalline and ferroelectric properties are studied. The desired chiral smectic C phase is retained up to 30 mol -% of chromophore. Also, first measurements of second harmonic generat ion have been performed.