In lyotropic liquid crystals the director at the boundary surfaces can be oriented by an external magnetic field, with a time constant ${\mathrm{\tau }}_{\mathit{s}}$ about ${10}^3$ times greater than that in the bulk. Measurements of ${\mathrm{\tau }}_{\mathit{s}}$ are presented for a lyotropic sample of potassium laurate, decanol, and water in the nematic calamitic phase (${\mathit{N}}_{\mathit{c}}$) in the vicinity of the nematic-isotropic transition. It is shown that ${\mathrm{\tau }}_{\mathit{s}}$ decreases linearly in the ${\mathit{N}}_{\mathit{c}}$ phase when the temperature approaches ${\mathit{T}}_{\mathit{c}}$ [Oliveira, Figueiredo Neto, and Durand, Phys. Rev. A 44, 825 (1991)].

• Received 22 September 1993

DOI:https://doi.org/10.1103/PhysRevE.49.629