Ew. Hansen et al., WATER-SATURATED MESOPOROUS MCM-41 SYSTEMS CHARACTERIZED BY H-1-NMR SPIN-LATTICE RELAXATION-TIMES, Journal of physical chemistry, 99(12), 1995, pp. 4148-4154
Combining spin-lattice relaxation time measurements and signal intensi
ty measurements vs temperature of water confined in mesoporous molecul
ar sieves (MCM-41 materials) gives information regarding the activatio
n enthalpy of bound water and the width of the log-normal distribution
of correlation times of the water molecules. Three different water ''
phases'' are observed which have significantly different relaxation st
rength. The overall spin-lattice relaxation rate is shown to be strong
ly dependent on the number of silanol protons. ''Analytical'' formulas
for the average spin-lattice relaxation rates are derived.