Preparation of a Novel Cross-Linked Polymer for Second-Order Nonlinear Optics

A novel cross-linked pyroelectric polymer with pronounced second-order nonlinear optical properties has been prepared. A multistep synthesis with several selective transformations including a kinetic resolution (transesterification) with the highly enantioselective Candida antarctica lipase B, yielded the monomer 4‘‘-{(R)-(−)-2-[(10-acryloyloxy)decyl]oxy}-3-nitrophenyl 4-{4‘-[(11-acryloyloxy)undecyloxy]phenyl} benzoate A2c which displayed a ferroelectric chiral smectic C phase with large spontaneous polarization (175 nC/cm2). The monomer was poled and subsequently cross-linked by in-situ photopolymerization in the surface-stabilized ferroelectric liquid crystalline state. The cross-linked pyroelectric polymer exhibited an electro-optical coefficient (r 22 − r 12) of 15−35 pm/V.