Deuterium and carbon-13 NMR spectroscopy were used to study both the high temperature uniaxial nematic and the low temperature biaxial nematic glass of a shape-persistent V-shaped mesogen. It was found that biaxial ordering determined in the domains of the latter has symmetry lower than D2h and is compatible with C2h symmetry or lower. In particular, elements of the ordering matrix including biaxial phase order parameters were determined from H2 NMR at two temperatures, one just below the glass transition, and the other deep inside the biaxial glass, which allowed for the characterization of the dominant molecular motions at these temperatures. C13 NMR magic angle spinning sideband patterns, collected both in the high temperature nematic phase and in the nematic glass, clearly show the difference between them in terms of the phase symmetry.

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