The proton intra-pair dipolar order relaxation time (T-1D) was measured for nematic methyl-deuterated para-azoxyanisole (PAA(d6)) as a function of both the temperature and concentration in perdeuterated PAA (PAA(d14)), at 27 MHz. Since the results coincide for all measured concentrations in all the nematic temperature range, we conclude that the intermolecular contribution to the relaxation of the dipolar energy in this compound is negligible, at the studied frequency. The observed temperature dependence of T-1D is typical of the order fluctuations of the director (ODF), which clearly indicates that the ODF is the relevant mechanism producing dipolar order relaxation, in accordance with previous field cycling experiments. (C) 2002 Published by Elsevier Science B.V.