Electron crystallography and organic materials with non-linear optical properties

Results of electron microscopic studies of crystal structures of a number o f bis-benzylidene cyclohexanones are presented. It is shown that some of th ese compounds are efficient crystalline non-linear optically active (NLO) c hromophores with second harmonic generation (SHG) properties. Appropriately functionalized chromophores of this type can be used as a polycondensation comonomer to produce partly crystalline main-chain NLO-active polymers. El ectron diffraction crystal structural data, obtained for very small crystal s, allowed us to get reasonable estimations of macroscopic crystal NLO-coef ficients, relating quantum-chemically calculated molecular first hyperpolar izability components to crystal axes.