Strain-field measurements and in situ polarized light microscopy have been used to evidence a hysteretic, irreversible electric-field-induced transition to a quasimonodomain rhombohedral phase in [111](C)-oriented, pseudo-orthorhombic PZN-8PT [0.92Pb(Zn1/3Nb2/3)O-3-0.08PbTiO(3)]. This first-order transition most likely occurs following the simplest path O-M-B-R, i.e., via polarization rotation in the (10-1)(C) plane. The measured strain-field loops are compared to those for rhombohedral, [111](C)-oriented PMN-28PT [0.72Pb(Mg1/3Nb2/3)O-3-0.28PbTiO(3)] and PMN-33PT [0.67Pb(Mg1/3Nb2/3)O-3-0.33PbTiO(3)] where no electric-field-induced transition is possible. (C) 2005 American Institute of Physics.