COMPARATIVE-STUDY OF HELICAL PITCH AND ELECTROOPTICAL BEHAVIORS OF HIGHLY TWISTED S-C-ASTERISK AND SC-ASTERISK-ALPHA PHASES

The helical pitch measurement of a new fluoro substituted tolan deriva tives series have revealed a strong torsion in all the phases (S-C, T GB(A), TGB(C)). The compound n=12 (FH/FH/HH-12BTMHC) exhibits an extre mely small pitch value of about 0.06 mu m in the SC phase. Such a sma ll pitch value has only been observed in the SCalpha phase of a thiob enzoate series. A comparative electro-optical and thermal pitch behavi our study of the SC and SC*alpha phases is performed in order to know if the switching current peaks in the SCalpha phase are directly lin ked up to its structure.