Abstract
We have investigated the viscoelastic behaviour exhibited by chiral smectic C* phases in homeotropic orientation. For an appropriate scattering geometry and using the light scattering technique, the orientational diffusivities
associated with the Goldsone mode in ferro- and antiferroelectric phases of C
11
thiobenzoate and C
8
tolane compounds have been measured.
(SmC
A
*) is about 100 times weaker than
(SmC*). This divergence may be largely attributed to the mode of the molecular arrangement in ferro- and antiferroelectric phases, in spite of the same helical structure observed in the two phases.