CB7CB, as expected for the
cholesteric phase with a helix of a pitch within the range of
optical wavelengths and the nematic phase, which is not
compressible, respectively. The value of B rises stepwise at the
N(*)-NTB(*) phase transition to 2×106 Pa for SB 3/5 and 2×
105 Pa for CB7CB, and further sharply increases with lowering
temperature (Figure 4) reaching the values 4×107 Pa in
the NTB* phase of SB 3/5 and 4×106 Pa in the NTB phase of
CB7CB. In both, CB7CB and SB 3/5, the values of B that are
typical for smectic phases[15, 16] were measured. The lower
value of B found for CB7CB compared with SB 3/5 might be