Advertisement

Comments on the Relaxation Process in the Cholesteric-Nematic Transition

  • R. A. Kashnow
  • J. E. Bigelow
  • H. S. Cole
  • C. R. Stein

Abstract

The relaxation process by which a field-aligned nematic state returns to a helicoidal structure has been the subject of several studies. In this paper, we report some new transient optical and capacitive measurements which emphasize the dependence of the relaxation on sample boundary conditions. Homeotropic samples exhibit a delay time after field removal, followed by nucleation of the decay sequence about isolated points. During the decay, the capacitance decreases monotonically, but the light-scattering transient is structured even in the absence of polarizing optics. A spiral domain structure is observed for these samples. For samples with parallel boundary conditions, the transient capacitance data exhibit a minimum which supports earlier inferences of a tilted-Grandjean-planar structure.

Keywords

Relaxation Process Effective Dielectric Constant Director Distribution Capacitive Measurement Domain Texture 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    E. Sackmann, S. Meiboom, and L.C. Snyder, J. Am. Chem. Soc. 89, 5981 (1967).CrossRefGoogle Scholar
  2. 2.
    J.J. Wysocki, J. Adams, and W. Haas, Phys. Rev. Lett. 20, 1024 (1968).CrossRefGoogle Scholar
  3. 3.
    P.G. de Gennes, Sol. State Comm. 6, 163 (1968).CrossRefGoogle Scholar
  4. 4.
    R.B. Meyer, Appl. Phys. Lett. 12, 281 (1968).CrossRefGoogle Scholar
  5. 5.
    The dynamics of the transition in samples with one free boundary have been studied by J. Prost and H. Gasporoux, Mol. Cryst. Liq. Cryst., to be published.Google Scholar
  6. 6.
    J.J. Wysocki, J. Adams, and D.J. Olechna, “Liquid Crystals and Ordered Fluids,” ed. J.F. Johnson and R.S. Porter, (Plenum Press, Inc., New York, 1970), p. 419.Google Scholar
  7. 7.
    J.J. Wysocki, Mol. Cryst. Liq. Cryst. 14, 71 (1971).CrossRefGoogle Scholar
  8. 8.
    T. Ohtsuka and M. Tsukamoto, Japanese J. Appl. Phys. 12, 22 (1973).CrossRefGoogle Scholar
  9. 9.
    R.A. Kashnow and H.S. Cole, Fourth International Liquid Crystal Conference, Kent, Ohio, 1972; Mol. Cryst. Liq. Cryst., to be published.Google Scholar
  10. 10.
    R.B. Meyer, Appl. Phys. Lett. 14, 208 (1969).CrossRefGoogle Scholar
  11. 11.
    F.J. Kahn, Appl. Phys. Lett. 22, 386 (1973).CrossRefGoogle Scholar
  12. 12.
    F. Rondelez and J.P. Hulin, Sol. State Comm. 10, 1009 (1972), and references therein.CrossRefGoogle Scholar
  13. 13.
    C.J. Gerritsma and P. Van Zanten, Phys. Lett. 37A, 47 (1971).Google Scholar
  14. 14.
    J. Adams, W. Haas, and J. Wysocki, Mol. Cryst. Liq. Cryst. 8, 9 (1969).CrossRefGoogle Scholar
  15. 15.
    P.E. Cladis and M. Kleman, Mol. Cryst. Liq. Cryst. 16, 1 (1972).CrossRefGoogle Scholar
  16. 16.
    P.G. de Gennes, Mol. Cryst. Liq. Cryst. 7, 325 (1969).CrossRefGoogle Scholar
  17. 17.
    Y. Bouligand, J. de Phys. 33, 525 (1972).CrossRefGoogle Scholar
  18. 18.
    E. Jakeman and E.P. Raynes, Phys. Lett. 39A, 69 (1972) report very short decay times which may characterize the slope of the initial change in light transmission.Google Scholar
  19. 19.
    This probably corresponds to the “self-orientation” effects described by S. Sato and M. Wada, Japanese J. Appl. Phys. 11, 1566 (1972).CrossRefGoogle Scholar
  20. 20.
    J.P. Hulin, Appl. Phys. Lett. 21, 455 (1972).CrossRefGoogle Scholar
  21. 21.
    M. Klernan and J. Friedel, J. de Phys. 30C, 4 (1969).Google Scholar

Copyright information

© Plenum Press, New York 1974

Authors and Affiliations

  • R. A. Kashnow
    • 1
  • J. E. Bigelow
    • 1
  • H. S. Cole
    • 1
  • C. R. Stein
    • 1
  1. 1.General Electric Corporate Research and DevelopmentUSA

Personalised recommendations