Time-resolved observation of isothermal phase transition of liquid crystals triggered by photochemical reaction of dopant

Abstract

A mixture of 4-butyl-4′-methoxyazobenzene (BMAB) and 4-n-pentyl-4′-cyanobiphenyl (5CB)([BMAB]/[5CB]= 0.03) undergoes an isothermal phase transition on pulse irradiation at 355 nm (10 ns fwhm), in which the relaxation from the nematic to the isotropic phase was completed within ∼ 100 ms as shown by time-resolved birefringence measurements.