We report the realization of a polarimetric surface plasmon resonance imaging system capable of dynamically resolving a change in the optical anisotropy of biochemical films. Anisotropies as small as 10(-3) refractive index unit on nanometer-thick samples can be resolved. As an example, we present here the dynamical anisotropy obtained by the electrical patterning of a film consisting of a self-assembled monolayer deposited on gold, covered with a phospholipid hemimembrane.