  We present the time integrated and time resolved spectral analysis of a
sample of bright bursts selected from the BATSE archive. We fitted four
different spectral models to the time integrated and time resolved spectra of
the flux pulses. We point out that the found (marginal) differences in the
parameter distributions can be ascribed to the different spectral shape of the
employed models and that a smoothly curved model best fits the observed
spectra. We characterize the spectral shape of bright bursts and compare the
low energy slope of the fitted spectra with the prediction N(E) = E^{-2/3} of
the synchrotron theory, finding that this limit is violated in a considerable
number of time resolved spectra around the peaks, both during the rise and
decay phase.
