SI-29 AND O-17 RELAXATION IN H8SI8O12 IN SOLUTION

Silicon-29 and oxygen-17 NMR relaxation data have been obtained for th e spherosiloxane H8Si8O12 in perdeuteriocyclohexane solution at 303 an d 323 K. The spin-lattice relaxation rates and the nuclear Overhauser enhancement factors for silicon were used to determine the dipole-dipo le contributions to the relaxation rates which, together with the know n silicon-proton distance, yield the rotational correlation times for the silicon-proton axis. The oxygen linewidths provide the quadrupolar spin-spin relaxation rates, which were used to estimate a quadrupole coupling constant for oxygen-17 of 4.9 +/- 0.5 MHz.