The water proton spin-lattice relaxation rate was measured in Fe conta
minated water filled porous glasses with pore diameters of 548 and 291
7 Angstrom at 0.65T at room temperature as a function of pore hydratio
n. Two distinct regimes could be defined. A ''wet'' pores regime (0.6<
V-0/V<1) and a regime with water only within the pores (1<V-0/V<4), wh
ere V-0 is the pore volume and V the water volume. In both regimes, th
e proton relaxation rate varies linearly with V-0/V. A small Fe ion co
ncentration in porous silica glass water remains constant while the hy
dration of pores is changed by a factor of approximate to 4, which is
a necessary assumption to model the observed proton spin-lattice relax
ation rate. Such a constant small concentration premise agrees with th
e Langmuir isotherm, which for systems with large surface to volume ra
tios (S/V-0), predicts a constant small volume concentration. In the t
wo studied porous glasses with S/V-0 of 9.2X10(6) and 42X10(6) m(-1),
the condition for large S/V-0 was satisfied, while the Fe volume conce
ntration which was -1 mM was small, as required. An analysis of the pa
ramagnetically enhanced proton relaxation is presented. (C) 1996 Ameri
can Institute of Physics.