AbstractThe proton nuclear magnetic relaxation rate, 1/T1, is reported as a function ofd5‐glycerol concentration for aqueous manganese(II) ion solutions over a range of magnetic field strengths corresponding to proton Larmor frequencies between 0.01 and 38 MHz. The data are analyzed in terms of the Solomon, Bloembergen, and Morgan equations which are found to be sufficient to account for the relaxation data over the field and concentration ranges studied. These data provide a useful reference for the viscosity dependence of manganese(II)‐ion‐induced magnetic relaxation in aqueous systems and a useful comparison with macromolecule bound manganese(II)‐ion‐induced relaxation where the theory is less s