Nonlinear optically active polymer

SPANGLER AND HAVELKA Nonlinear Optic-Active Polymers... 

Kimura, et al. synthesized polymers bearing oligo-aromatic esters as side chains to form second-order nonlinear optical active polymers on the basis of architecture. The cut-off wavelength ( co) of these polymers is shorter than the visible region, i.e., kco ca. 330-370 nm, which are much shorter than the typical second order nonlinear optics polymer containing chromophores like azobenzene. These polymer films exhibit good transparency in the visible region. The second-order nonlinear optical coefficient, is 2.2-9.S pm.V... 

Spangler, C. W. and Havelka, K. O., Design of new nonlinear optic-active polymers. Use of delocalized polaronic or bipolaronic charge states, in Materials for Nonlinear Optics Chemical Perspectives (ACS Symp. Ser., 455), Marder, S. R., Sohn, J. E., and Stucky, G. D., Eds., American Chemical Society, Washington, D.C., 1991, 661. 

Nonlinear Optically Active Polymers for Waveguide Application... 

Dehydration or Chemical Stabilization. The removal of surface silanol (Si—OH) bonds from the pore network results in a chemically stable ultraporous soHd (step F, Fig. 1). Porous gel—siHca made in this manner by method 3 is optically transparent, having both interconnected porosity and sufficient strength to be used as unique optical components when impregnated with optically active polymers, such as fiuors, wavelength shifters, dyes, or nonlinear polymers (3,23). 

Optically active polymers are potentially very useful in areas such as asymmetric catalysis, nonlinear optics, polarized photo and electroluminescence, and enantioselective separation and sensing.26 Transition metal coupling polymerization has also been applied to the synthesis of these polymers.27 For example, from the Ni(II)-catalyzed polymerization, a regioregular head-to-tail polymer 32 was obtained (Scheme 9.17).28 This polymer is optically active because of the optically active chiral side chains. 

J. L. Bredas and R. Silby, Conjugated Polymers The Novel Science and Technology of Highly Conducting and Nonlinear Optically Active Materials, Kluwer Academic, Boston, 1991. 

A number of liquid crystalline polyphosphazenes with mesogenic side groups have been prepared (48—50). Polymers with nonlinear optical activity have also been reported (51). Polyphosphazene membranes have been examined for gas, liquid, and metal ion separation, and for filtration (52—54). There is interest in phosphazene—organic copolymers, blends, and interpenetrating polymer networks (IPNs) (55—61) to take advantage of some of the special characteristics of phosphazenes such as flame retardance and low temperature flexibility. A large number of organic polymers with cydophosphazene substituents have been made (62). 

Fischer, P. Koetse, M. Laschewsky, A. Wischerhoff, E. Jullien, L. Persoons, A and Verbiest, T. (2000) Orientation of Nonlinear Optical Active Dyes in Electrostatically Self-Assembled Polymer Films Containing Cyclodextrins, Macromolecules 33, 9471-9473. 

However, the particular synthetic requirements in the preparation of conjugated polymers have thus far severely limited the number of similarly hierarchically structured examples. Pu et al. reported different types of conjugated polymers with fixed main-chain chirality containing binaphthyl units in their backbone which exhibited, for example, nonlinear optical activity or were used as enantioselective fluorescent sensors [42—46]. Some chirally substituted poly(thiophene)s were observed to form helical superstructures in solution [47-51], Okamoto and coworkers reported excess helicity in nonchiral, functional poly(phenyl acetylenejs upon supramolecular interactions with chiral additives, and they were able to induce a switch between unordered forms as well as helical forms with opposite helical senses [37, 52, 53]. 

Kohler BE (1990) A simple model for linearpolyene electronic structure. J Chem Phys 93 5838-5842 Kohler BE (1991) Electronic properties of linear polyenes. In Bredas JLand Silbey R(eds) Conjugated Polymers The novel science and technology of conducting and nonlinear optically active materials, pp 405-434. Kulver Press, Dordrecht Kohler BE(1993a) Octatetraene photoisomerization. ChemRev 93 41-54... 

G. Gustafsson, W.R. Salaneck, J. Laakso, M. Loponen, T Taka. J.-E. Osterholm, H. Stubb, and T. Hjertberg, in Conjugated polymers Novel Science and Technology of Conducting and Nonlinear Optically Active Materials (Ed.) J.-L. Bredas and R. Silbey, Kluwer, Dordrecht... 

In the latter system, there appears to be competition between alignment and thermal motion, so the best results were obtained when the poling was carried out close to the 298 K rather than at higher temperatnres the nematic to isotropic transition was = 373 K. More recent attempts have been made to improve the poled systems by incorporating the nonlinear, optically active molecnles into the polymer chain structure and comb-branch liquid crystalline polymers with R and the new group... 

L.S. Sapochak, D.W. Polls, L.R. Dalton and C.W. Spangler, Asymmetrical diphenylpolyene pendant polymers for nonlinear optical activity. Optical and Electronics Properties of Polymers, MRS Proceedings, Vol. 214, J.A. Emerson and J.M. Torkelson eds., 1991, pp 73-78. 

Orientation of nonlinear optical active dyes in electrostatically self-assembled polymer films containing cyclodex-trins was studied. "The concept of molecular recognition of organic chromophores by coordinating polymers was another novel approach in the construction of nonlinear optical supramolecular assemblies. 

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