Signal dependence on diffusion time has been reported in various tissues and has been connected to cellular restrictions. It is conceivable, however, that it partly originates from relaxation weightings of different compartments. In this study, we investigate the diffusion time dependence of the diffusion tensor in brain tissue at 1.5 T, 3 T and 7 T using a stimulated echo sequence. The results show clear time dependencies of axial and radial diffusivity. 7 T data show a reduction of both diffusivities, indicating a non-negligible role of compartmental relaxation weighting effects.