Nonlinear optical chromophores having tetrahydrocarbazole donor groups, lyotropic compositions containing the same, and methods of poling such compositions
Nonlinear optical chromophore compositions which display lyotropic nematic liquid crystal phases in polar organic solvents and provide a mechanical anisotropic effect allowing for the formation of a non-centrosymmetric chromophore-polymer matrix without the application of an electric field.
1 . A lyotropic composition comprising the nonlinear optical chromophore of the general formula (I):
D -Π- A
wherein D represents an organic electron-donating group; A represents an organic electron-accepting group having an electron affinity greater than the electron affinity of D; and Π represents a Π-bridge between A and D; wherein the electron-donating group D comprises a tetrahydrocarbazole moiety having the general formula (II):
wherein R 1 represents a moiety other than hydrogen, wherein R 2 represents a moiety selected from hydrogen, halides, alkoxy groups, linear or branched alkyl groups, and aryl groups, wherein R 3 represents a moiety selected from hydrogen and linear or branched alkyl groups, wherein R 4 represents a moiety selected from hydrogen and linear or branched alkyl groups, and wherein R 5 which may optionally be present represents a fused aliphatic or aromatic ring having 3 to 5 carbon atoms.
2 . The lyotropic composition of claim 1 , wherein R 1 represents a moiety selected from the group consisting of branched alkyl groups, and aryl groups.
3 . The lyotropic composition of claim 2 , wherein R 1 represents a moiety selected from substituted and unsubstituted benzyl groups.
4 . The lyotropic composition of claim 2 , wherein R 1 represents an aryl group substituted with a silyl group.
5 . The lyotropic composition of claim 4 , wherein R 1 represents an aryl group substituted with a triaryl-substituted silyl group.
6 . The lyotropic composition of claim 5 , wherein R 1 represents 4-(triphenylsilyl)-phenylmethyl.
7 . The lyotropic composition of claim 6 , wherein the A is selected from the group consisting of: