  The structural changes in Sr(0.66)Ba(0.34)Nb2O6 single crystal fibers when
the temperature decreases from 295 to 10 K is investigated by dielectric
constant measurements and Raman spectroscopy. The anomaly observed in the plot
of e is associated to the variation in the intensity and frequency of some
Raman modes. We observe that the intensity of some low energy modes has a very
singular behavior for the y(xz)y scattering geometry. In the high energy region
(> 850 cm-1), a band at ~ 880 cm-1 disappears when the temperature is cooled
down to 10K for the y(xz)y geometry and shifts to higher energy values for the
y(zz)y geometry.
