NMR relaxation studies of porous sol-gel glasses

2H relaxation times T1, T1ρ and T2 for D2O in silica sol-gels are used to monitor porosity and surface interactions within the silica framework as a function of aging. Tetramethoxysilane gels are compared with composites containing low levels of poly(vinyl alcohol) (PVA) prepared under acidic conditions. Non-exponential decay of magnetisation in T1ρ and T2 experiments is attributed to the fractal nature of the pore structure.