Influence of Electric and Magnetic Fields on the Molecular Alignment in EBBA

The effects of external de and af electric fields of strengths up to 25kV/cm on the nematic liquid crystal p-ehtoxybenzylidene-[pacute]-n-butyl aniline (EBBA) are investigated. The effectiveness of electric fields and of high magnetic fields in producing molecular alignment are compared. Changes in the molecular alignment are observed in terms of changes in the rf dielectric constant. These measurements are as fruitful as microwave measurements in studying the degree of ordering of molecules in bulk samples of liquid crystals. The threshold voltages for chevron formation in the dielectric regime are found to be considerably lower than the threshold voltages necessary induce changes in dielectric constant in the same regime.