Measurements of T1 and T2, the spin-lattice and spin-spin relaxation times, are reported for Na23 and Cl35 nuclei in NaCl from room temperature to the melting point. For single-crystal samples below 700Â°K, T1 is due to quadrupolar interactions of the nuclei with lattice vibrations and diffusing vacancies, and T2 arises from the dipolar interaction between nuclei. A jump frequency for positive ion vacancy motion of 4×107 sec-1 at 510Â°K is obtained, in good agreement with conductivity measurements. At higher temperatures a number of anomalous features appear and possible explanations are discussed. © 1964 The American Physical Society.