Modern Polymer Spect..

2.5 Electric Field-Induced Orienfation 55
n 10 rn 30 40 50
TIME / ms
Figure 2-22. Normalized absorbance versus time during orientation and relaxation of the solventand
solute-specific functionalities (see Figure 2-21).
on the nematic liquid-crystal 4-cyano-4'-pentylbiphenyl (often denoted as 5CB)
by means of time-resolved FTIR spectroscopy under the conditions of dynamic
reorientation give evidence for different reorientation times of its non-ridgidly
bonded fragments.
Although Figure 2-2 1 shows that neither the orientation nor the relaxation of the
solute and solvent molecules is complete under the experimental conditions, we
expected that the delay phenomena between the solvent and solute molecules would
be clearly expressed in a normalized absorbance versus time plot. This plot, however,
as shown in Figure 2-22, does not provide any indications of such a behavior.
In othei- words, the reorientation rates are equal for the solvent and the solute.
Without drawing any general conclusions from a single example, the present results
show that one may expect similar behavior in other nematic solutions.
2.5.5 Reorientation Dynamics of a Ferroelectric Side-Chain
Liquid-Crystalline Polymer in a Polarity-Switched
Electric Field
The surface-stabilized ferroelectric liquid crystals in the smectic C* (SmC*) phase
are among the most interesting types of liquid-crystalline systems because of their
potential applications in high-resolution flat panel displays and fast electro-optical
devices [73-761. Within this class of compounds, ferroelectric liquid-crystalline polymers
(FLCPs) have gained theoretical and practical interest as systems which combine
the properties of polymers and ferroelectric liquid crystals. This combination is
achieved by attaching the ferroelectric mesogen to a main chain via a flexible spacer