Variable temperature, solid-state deuterium (H-2) NMR spectroscopy has been used to probe the rather complex head group dynamics of the surfactant cetyltrimethylammonium bromide-d(9) (CTAB-d(9)) in bulk. Heating and cooling runs were made as the surfactant underwent supercooling. H-2 NMR line shape simulations were used to identify the hierarchy of the molecular motions of CTAB as a function of temperature. Fast continuous methyl rotations about the N-C-methyl axes and 3-fold jumps about the main chain C-N axis were present at all of the temperatures from -40 to 120 degrees C. With heating, the spectra were consistent with CTAB molecules starting 180 degrees flips about the hydrocarbon chain molecular axis around 0 degrees C, which continued to flip with increasing flip rates up to 80 degrees C. At 90 degrees C, the flips changed to rotation of the CTAB molecules about the hydrocarbon chain axis and that rotation continued to 120 degrees C. Comparison of spectra of bulk CTAB at different temperatures from heating and cooling runs revealed that the rotation about the long axis of the hydrocarbon chains started at around 90 degrees C on heating, however, it does not freeze out until between 70 and 80 degrees C because of supercooling.