Orientational order in nematic, smectic A, and smectic C phases of doped with dichroic dye§

Oriental behaviour of some homologues of 4-n-pentyl-phenylthio-4′-n-alkoxybenzoate doped with dichroic dye

“…This can be a confirmation of the fact that there exists a strong correlation between the order parameter and the shift of the phase transition temperatures of the dye/liquid crystal mixture with respect to that of pure liquid crystal. Such correlation had been found previously for dyes 1-3 dissolved in 8S5 [18] and 10S5 [19], as well as for many other dye/liquid crystal systems [9,[20][21][22]. Figure 3(a) shows the order parameters <P 2 > A (crosses), <P 2 > F (squares) and <P 4 > F (circles) as a function of the reduced temperature for dye 1 in 7S5 in the nematic phase, whereas in Figs.…”

“…3(b) and 3(c), do not take this fact into account. In the previous paper [18] we showed that the influence of the angle q on the results obtained is not very large. Even when one assumes that directions of the inclination of molecules in the tilted phases are fully ordered, <P 2 > A changes at most of 2%.…”

“…Figure 3(a) shows the order parameters <P 2 > A (crosses), <P 2 > F (squares) and <P 4 > F (circles) as a function of the reduced temperature for dye 1 in 7S5 in the nematic phase, whereas in Figs. 3(b) and 3(c), for comparison, the temperature dependence of <P 2 > F and <P 4 > F values for mixtures of dye 1/8S5 [18] and dye 1/10S5 [19], respectively, in the SmC, SmA and N phases are presented.…”

Role of specific and nonspecific intermolecular interaction in electro-optical response of doped 6CHBT nematic liquid crystal with azo dyes

“…1. All measurements of the Kerr constant were made using the nulled intensity method [15,18], which involves nulling the optical response resulting from the application of electric field across the Kerr cell. He\ \Ne laser emitting at wavelength of 632.8 nm with power of 5 mW has been used as a probe beam.…”

“…Due to high values of solubility, order parameter, permanent dipole moment and dichroic properties in liquid crystal displays (LCDs) and also the highest efficiency for LC nonlinearity enhancement, azobenzene dyes are attractive as dopants of LC [15,16]. Since intermolecular interactions between azo dyes and liquid crystal environment contain either nonspecific (dipole-dipole) or specific (e.g.…”