The primary intent of this research was to determine the influence of three common degradation mechanisms, dark area defects, facet degradation and contact degradation, on the operational lifetime of GaAs edge-emitting semiconductor lasers driven by continuous current at 100 degree(s)C. Inherent to this work was the quantified characterization of the lasers during their operation. Power vs. current characterizations were conducted at room temperature on each laser before and after exposure to 100 degree(s)C as well as at the beginning and end of each laser's exposure to 100 degree(s)C. An additional means of examining laser degradation came from measuring the current required over time to maintain a constant power output of 5, 7, or 10 mW at the elevated temperature. The research demonstrated that facet degradation and contact degradation were minor contributors to the bulk of the data base's degradation. Dark area defects were thus the primary degradation mechanism as the data's gradually increasing current necessary to maintain constant output will attest. An HF acid rinse on one laser, reacting aggressively to local crystal defects, highlighted the growth of dark area defects toward the lasing cavity due to continued lasing. One trend was left unexplained. As a whole, the lasers performed with higher slope efficiencies at elevated temperature, contrary to previously documented research. This topic deserves future research.