Observation of Intermediate Smectic A Structure at the Phase Transition Nematic-Smectic C in 4,4′-di-n-Heptyloxyazoxybenzene

Using different boundary conditions in thin film of 4,4′-di-n-heptyloxyazoxy benzene and studying the microscopic textures as well as the depolarized Rayleigh light scattering, an intermediate smectic A-like state during the nematic-smectic C phase transition was observed.