We have carried out photoacoustic experiments to study the layered electroceramics Bi4-xRxTi3O12 (R-x = Pr, Nd, Gd, Dy), with x = 0.8. Results are shown in terms of successive analyses performed on functions, PA(t, T-i), which result from the interaction of the laser beam with the crystalline lattice. Previous permittivity experiments performed in the materials suggested anomalous ferroelectric behavior. Using a pulsed Nd:YAG laser (10 Hz, 5 ns pulse width), photoacoustic experiments were run from room temperature up to 800 degreesC. Perturbations in the resultant correlation curves can be interpreted as the existence of a wide set of different transition temperatures in the material, such as are believed to occur in relaxors. From these experiments, we conclude that the temperature dependence of non-classical ferroelectrics can be more closely monitored. (C) 2003 Elsevier Science Ltd. All rights reserved.