Through the unique white-beam synchrotron radiation topography (WBSRT) method with several Al foils covering the sample, we have investigated in situ phase transition behavior in unpoled relaxor ferroelectric 0.92Pb (Zn1/3Nb2/3)O-3-0.08PbTiO(3) (PZN-8%PT) crystals and found it was anomalous to that reported previously. According to the ferroelectric domain growth behavior on heating and cooling, it was demonstrated that the unpoled PZN-8%PT crystal undergone three phase transitions, i.e., the rhombohedral-orthorhombic (R-O) phase transition at 75 degreesC, the rhombohedral-monoclinic or orthorhombic tetragonal (R-M/O-T) phase transition at 132 degreesC, and the monoclinic or tetragonal-cubic (M-C/T-C) phase transition at 262 degreesC. DSC analysis revealed that the R-O phase transition and the M-C/T-C transition was of the first-order, while the R-M/O-T one belonged to the second-order type. (C) 2003 Elsevier Science B.V. All rights reserved.