Electric Field Dependence of Variance in Helicoidal Pitch Distribution and of Light Transmittance in the Ferroelectric Liquid Crystal DOBAMBC

In S* C phase of DOBAMBC, electric field dependence of variance of the helicoidal pitch and of light transmittance was studied using a photodensity analyzer consisting of a video camera and a personal computer. When a temperature deviation from the transition point Tc between SA and S* C is large, the minimum transmittance is observed at the field of the maximum variance of the pitch with both increasing and decreasing field. This shows that an increase in the variance induces an increase in light scattering. The increase in variance is qualitatively explained as the result of imhomogeneous realignment of pitch by applying the field to finite size domains.