SYNTHESIS AND ANISOTROPIC BEHAVIOR OF NEW LADDERLIKE POLYSILSESQUIOXANES WITH SIDE-ON AND END-ON FIXED NLO CHROMOPHORES

This report deals with a new kind of ladderlike polysilsesquioxanes wi th nonlinear optical (NLO) chromophores which are laterally (side-on) or terminally (end-on) fixed on the ladderlike macromolecular backbone s. These new functionalized ladderlike polysiloxanes were synthesized via hydrosilylation reaction of a series of diphenyl acetylene (tolan) derivatives (for side-on fixed) or vinyl-terminated diphenylethylene (stilbene) derivatives (for end-on fixed) with ladderlike polyhydrosil sesquioxane [H-T] or its copolymers CPH-TI. The anisotropic behavior o f the mesogenic polymers were studied by IR dichroism, temperature-var iable X-ray diffraction and optical polarized microscopy. The ''Rowboa t model'' for side-on fixed liquid crystalline polysilsesquioxane was confirmed by IR dichroism and X-ray diffraction observations.