  Dielectric, anelastic and ^139La NMR relaxation measurements have been made
on the relaxor ferroelectric Pb(1-3x/2)La(x)Zr(0.2)Ti(0.8)O(3) (PLZT) with x =
0.22. The dielectric susceptibility exihibits the frequency dispersive maximum
due to the freezing of the polar degrees of freedom around T ~250 K. The
anelastic and especially NMR relaxation, besides this maximum, indicate an
intense and broad component at lower temperatures, attributed to rotational
modes of the O octahedra, weakly coupled to the polar modes. It is discussed
why such short range rotational instabilities, known to occur in the Zr-rich
rhombohedral region of the PLZT phase diagram, might appear also in the Ti-rich
region.
