Molecularly doped liquid crystalline

Molecularlv Doped Thermotropic Liquid Crystalline Polymer. The idea of the nonlinear optical medium which is the subject of this paper results from a synthesis of the ideas of the discussion above and a few concepts from nonlinear optical molecular and crystal physics. As discusssed several places in this volume, it is known that certain classes of molecules exhibit tremendously enhanced second-order... 

An earlier study of the molecularly doped polymer liquid crystalline system shown in Figure 6.9 revealed more complex behavior (27, 32). In this study, the amount of induced nonlinearity was path dependent, with the largest observed value occurring when poling was done near Tg ( 25 C). The host polymer exhibits a nematic-to-isotropic transition at = 100 C and a nematic texture between Tg and. Poling at 50 C produces a decrease in approximately 1 order of magnitude. The l/T dependence... 

FIGURE 5.30 Top Unidirectional rotation of molecular motor 41 in a liquid crystalline host, and associated HTPs. Bottom Colors of 41 doped LC phase (6.16 wt% in E7) in time, starting from pure (P,P)-trans-4 upon irradiation with >280 mn light at room temperature, as taken from actual photographs of the sample. The colors shown from left to right correspond to 0,10, 20, 30,40, and 80 s of irradiation time, respectively. Reprinted with permission from Reference 63. Copyright 2002 National Academy of Sciences. 

Among all the experimental investigations performed in anthraquinone-doped nematic liquid crystals, two results are worth being noted here as they highlight some important features of the microscopic intermolecular interactions involved in this phenomenon. In the first experiment, we have found that slight changes in the molecular structure of relatively simple anthraquinone dyes may lead to dramatic modifications of the macroscopic nonlinear optical properties of the liquid-crystalline host [22]. This is shown in Fig. 5.2... 

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