Starting in October of 2008 and continuing through April of 2009, the textit{Fermi} Gamma-ray Burst Monitor (GBM) observed three periods of activity from SGR J1550-5418. Over the course of these outburst periods, GBM observed several hundred bursts from this source. We have performed analysis on these three outburst periods, and identified significant evolution between the spectra of bursts between the first and the other two periods. While a single blackbody function best describes the bursts of the first period, a two black body model best describes those of the second; more than one model fits the bursts of the third period equally well (OTTB, BB+BB, Comptonized model).
These results show an evolution in the burst emission mechanism of the source. We have analyzed a sample of 66 bursts within the tail of the second outburst period to search for any spectral changes between the last two active periods, without success. Finally, we present a comprehensive review of all temporal and time-integrated spectral analyses of the entire set of GBM bursts from this source. In addition, we include an analysis of how the peak times of bursts relate to the phase of the source spin period.