4- -4 -nitrostilbene DANS

We have calculated lig and /Jzzz for 4-dimethylamino-4 -methylsulfonylstilbene (VI), and compared these data with values for 4-dimethyl-amino-4 -nitrostilbene (DANS, VII). We have also included the azo-derivatives VIII and IX in the comparison (Table I). Calculated values of j5z for III, IV, VI, and VII as a function of basis set size are shown in Figure 1. It is evident that in all of these cases, there is a single excited state that provides the largest contribution to the hyperpolarizability. 

The results from EFISH experiments are listed in Table IV along with the FF predictions. We note that the our measured values for 4-dimethylamino-4 -nitrostilbene (DANS) and 4-dimethylamino-4 -nitroazobenzene are consistent with previously published work (26,27). The theoretical predictions discussed previously show an excellent correlation with the actual measured values for (Mg)zPz. As predicted the nonlinearities of nitro-containing compounds are larger... 

To determine whether NLO chromophores can be immobilized in highly cross-linked matrices, experiments were carried out in which the high- molecules 4-(dimethylamino)-4 -nitrostilbene (DANS, 3) and Disperse Orange 1 (DOI, 4) were dispersed in an optical grade epoxy resin,... 

Molecules such as 4 -dimethylamino-4-nitrostilbene ( DANS , 1) possess the necessary electronic structure, and have very large p... 

Dopant orientation during and following electric field-induced poling can be studied continuously and in real time in order to examine the microenvironment surrounding the dopants in terms of the polymer relaxations and the applied corona field. In the results presented below, the SHG of 4-dimethylamino-4 -nitrostilbene (DANS) dispersed in polystyrene (PS) or poly(methyl methacrylate) (PMMA) matrices has been examined in corona poled films as a function of temperature in order to understand the effect of thermal conditions on the temporal stability of the dopant orientation. 

In this chapter, we present the fabrication parameters and optical performances of the packaged polymeric MZ waveguide modulator for photonic applications using a polymethyl methacrylate (PMMA-based side-chain polymer with 4-dimethylamino-4 -nitrostilbene (DANS). We discuss the design considerations for single-mode propagation at a wavelength of 1.3 fim in relation to the fabrication sequence. In particular, we discuss the optical power stability of our devices in detail. 

Second-order nonlinear optical properties require noncentrosymmetric structure. On the molecular level this is usually obtained by push-pull systems such as 4-7V,N-dimethylamino-4 -nitrostilbene (DANS) see Fig. 36a. But (/3> and subsequently will be zero if the macroscopic structure of the material is centrosym-metric. Therefore, polymers are usually poled to induce a noncentrosymmetric structure i.e., a high electric field is applied and the polar order is frozen in the glassy state. Problems are the relatively low polar order and its temporal and thermal instability. 

The parameters that can be changed at the molecular level are the relative electron affinities of the donor and acceptor groups and the length as well as the nature of the conjugated segment connecting the donor to the acceptor. The chemical structures of some of the NLO chromophores such as 4-(dimethyl-amino)-4 -nitrostilbene (DANS) (a). Disperse Red 1 (b), l-(2 -ethylhexyloxy)-2, 5-dimethyl-4-(4 -nitrophenylazo)benzene (EHDNPB) (c), N,N-diethyl-substituted... 

Figure 17 Electrochromic measurements of DANS (4-dimethylamino-4 -nitrostilbene) in PMMA at 125 °C. The change in absorption is measured at a wavelength of 435 nm.

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