Published online by Cambridge University Press: 21 March 2011
The magnetic field dependence of 1H spin lattice relaxation rates in noncrystalline macromolecular solids including engineering polymers, proteins, and biological tissues is described by a power law, 1/T1 = Aω0-b, where ω0 is the Larmor frequency, A and b are constants. We show that the magnetic field dependence of the proton 1/T1 may be quantitatively related to structural fluctuations along the backbone that modulate proton-proton dipolar couplings. The parameters A and b are related to the dipolar coupling strength, the energy for the highest vibrational frequency in the polymer backbone, and the fractal dimensionality of the proton spatial distribution.