The paper is devoted to application of a synchrotron radiation scattering method to the analysis of domain structure ofSr0.6Ba0.4Nb2O6 (SBN) samples. It is experimentally established that at high temperature there are polarizing centers of the varied size in the SBN-61 samples, with center distances down to the units of micron. Domain structure formation in SBN-61 is accompanied by partial disordering caused by increasing of polarization fluctuations. The polarization in the volume of the samples in question was correlated, and a direction of preferred correlation can change depending on the general ordering.