Time-integrated optical emission spectroscopy has been used to observe the plume produced during pulsed laser deposition (PLD) in oxygen of the ferroelectric oxide SrBi2Ta2O9 (SBTO). Line emission from atomic and singly ionized target material was observed, together with emission from atomic oxygen. Band emission from strontium oxide was also observed. Spatially resolved analysis of oxide emission and atomic emission together with the assumption of an optically thin plasma plume distant from the point of ablation indicated that oxidation occurred most readily at the interface between the visible plume and the background gas. The oxide content in the visible plume was seen to increase as the plume passed through the background gas. Analysis of line intensity ratios and widths allowed the plasma electron temperature and density of the plume to, be measured, with peak values of 7300 K and 1.2 x 10(17) cm(-3), respectively, measured at the laser spot. These results are of interest for the fabrication of SBTO thin films in particular, and for the deposition of complex oxides by PLD in an oxidizing atmosphere in general.