Azobenzene dyes

Figure 10 Reorientation of an azobenzene dye by photoisomerization with polarized light. Molecular representations of the lruns and cis forms of an azobenzene are represented by straight and bent shapes to illustrate how a trans-cis-trans cycle can effect a reorientation of the traru-azobenzene. If the inducing hght is polarized in the horizontal direction, the vertically oriented molecule will be unable to absorb the hght, and this orientation will therefore be photostable.

Similar behavior has been observed in polyisocyanates, which have been shown to possess a helical structure. Unlike polypeptides, polyisocyanates have no stereocenter in their backbone they therefore form a racemic mixture of left-handed and right-handed helices. 1221 Incorporation of chiral azobenzene dyes into the side... 

The input polarization dependence of p- and s-polarized SH light was measured to elucidate the molecular orientation of L and ML species. The results can be fitted well to the theory and the relative values of three non-zero elements of the surface susceptibility [63-65], which determine the molecular orientation, are obtained from the fitting. Since hyperpolarizability of azobenzene dyes is known to be dominated by a single element which is an element of the hyperpolarizability along the tc-jt moment direction [52], the tilt angle 0 can be estimated from the relative values of the surface susceptibility. 

Lefe, P., Fiorini, C. and Nunzi, J.-M. (1998). Anisotropy of the photo-induced translation diffusion of azobenzene dyes in polymer matrices. Pure Appl. Opt. 7 71-82. 

Solvatochromic effects have been studied in the visible absorption of azobenzene dyes 44 containing isothiazole, and heterocyclic derivatives. Selected maxima are shown in Table 7. 

Gille, K., Knoll, H., and Quitsch, K, (1999). Rate constants of the thermal cis-trans isomerization of azobenzene dyes in solvents, acetone/water mixtures, and in microheteroge-neous surfactant solutions. Int.J. Ghem. Kinet. 31, 337-350. 

Schonhoff, M., Chi, L. F., Fuchs, H, and Losche, M. Structural Rearrangements Upon Photoorientation of Amphiphilic Azobenzene Dyes Organized in Ultrathin Films on. Solid Surfaces. Langmuir 11, 163 (1995). 

Awangku Yusof, A. A. R., O Leary, S. V., and Mitchell, G. R. (1999). Temperature-tuned vector phase conjugation in azobenzene dye impregnated polymer films. Opt. Commun. 169, 333-340. 

Srikhirin, X, Laschitsch, A., Neher, D., and johannsmann, D. Light-induced softening of azobenzene dye-doped polymer films probed with quartz crystal resonators. Appl. Phys. Lett. 2000, 77, pp. 963-965. 

Xiao S, Lu X, Lu Q (2007) Photosensitive polymer from ionic self-assembly of azobenzene dye and poly(ionic liquid) and its alignment characteristic toward liquid crystal molecules. Macromolecules 40 7944—7950... 

I. Novel network polyurethane with azobenzene dye in the main frame, Macromolecules, 1995, 28, 6437 Nonlinear optical polymers. 2. Novel NLO linear polyurethane with dipole moments aligned transverse to the main backbone, Macromolecules, 1996, 29, 592. 

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