Deuteron and carbon magnetic resonance studies of supercooled liquid and glassy salol

Abstract

The glass-former salol was studied using carbon and deuteron NMR. For the 13C measurements protonated samples were used. For the deuteron experiments salol was selectively deuterated at the phenyl ring. The measurement of the spin-lattice relaxation times provides clear evidence for an anisotropic reorientation of the molecules in the supercooled liquid. Close to the glass transition a bimodal longitudinal magnetization recovery is observed which indicates the presence of relatively slow intramolecular degrees of freedom. From deuteron solid echo spectra this process is identified as a uniaxial large amplitude motion of the phenyl group which exhibits a broad distribution of correlation times.