Nuclear magnetic resonance spectroscopy in cholesteric liquid crystals .II. The blue phase

NMR spectroscopy is utilized to study the little understood ’’blue phase’’ of the cholesteric liquid crystals cholesteryl m‐fluorobenzoate and cholesteryl decanoate. The NMR spectra in the ordinary cholesteric phase has both structure and width; these features are reduced in the blue phase to the point where they resemble isotropic phase spectra. The presence of a wider than isotropic NMR line, however, indicates the presence of long‐range orientational order and provides data which place constraints on the possible structure of the blue phase. In addition, the results show considerable thermal hysteresis for the blue‐cholesteric transition in cholesteryl decanoate.