Baking (Pb, La)(Zr, Ti)O3 capacitors in a hydrogen atmosphere causes a significant loss of remanent polarization even at 150 °C. The hysteresis variations depend on the polarization states during baking. The hysteresis loop showed voltage shifts when the capacitor was polarized before baking, whereas it became a cramped shape when the baking was carried out on a virgin capacitor. Although remanent polarization diminished in all cases, saturation polarization was not suppressed. The clamped hysteresis loop can be described as an average of two loops shifted to positive and negative voltages. The results indicate that the loss of remanent polarization is not due to the suppression of switching, but due to the shift of the hysteresis of each domain larger than the coercive voltage. © 1999 American Institute of Physics.