Following either intrinsic protein fluorescence (if possible) or by labeling the protein with a suitable probe one would expect the polarization of the system to decrease upon dissociation of the dimer into monomers since the smaller monomers will rotate more rapidly than the dimers (during the excited state lifetime). 
F
F
F
F
F
F
Hence for a given probe lifetime the polarization (or anisotropy) of the monomer will be less than that of the dimer
Polarization methods are ideally suited to study the aggregation state of a protein.  Consider, for example the case of a protein dimer - monomer equilibrium.
F
F
Lower P
Higher P
Polarization in Protein I