The as-sintered Pb(Zn(1/3)Nb(2/3))(0.5)(Zr(0.47)Ti(0.53))(0.5)O(3) samples were annealed in oxygen and nitrogen. Both annealed specimens exhibited improved degree of relaxation compared with as-sintered specimens. However, the mechanisms inducing enhancement of relaxation were different in the two kinds of specimens. For the oxygen annealed sample, oxygen vacancies were partially filled, which induced the macro-microdomain transition and resulted in the increase of relaxation degree. Whereas, for the nitrogen annealed specimen, the emergence of pyrochlore phase was inevitable due to the flowing reductive atmosphere, the pyrochlore phase broke the long-range transition invariance of perovskite structure and played a key role in improving the relaxation. (C) 2009 Elsevier Ltd. All rights reserved.