Time resolve optical hole burning is used to study spectral diffusion
of the H-3(4) double-line arrow pointing left and right 1D2 transition
in a LaF3:Pr3+ in a time scale of millisecond to seconds. The evoluti
on of the hole depended strongly on the magnitude of an applied magnet
ic field. The amount of spectral diffusion observed was larger than wh
at could be explained through F-Pr dipolar interactions.