Fourier transforms of the electron spin echo envelope modulation (FTESEEM) patterns of deuterated TANOLD spin probes (4-hydroxy-2,2,6,6-piperidinyl-1-oxy-d17) in the amine-cured diglycidyl ether of bisphenol A epoxy (DGEBA) at room temperature show two pairs of deuterium lines displaced about the free deuterium frequency (2.2 MHz) which are assigned to the electron-nuclear hyperfine couplings of inequivalent -CD3 groups of the nitroxide. Conformational asymmetry of the -CD3 groups accounts for the experimentally observed two pairs of spectral lines at room temperature and the disappearance of one pair of lines at 100 K. In this model, it is suggested that two conformational states of the spin probe molecules are thermally populated as the temperature is increased from 100 K to room temperature. Continuous wave electron-nuclear double resonance (ENDOR) spectra support the FTESEEM results. Nuclear quadrupole interactions, as an alternative explanation for the observed splittings, are shown not to fully account for the experimental observations.