We report time-resolved measurements of diatomic aluminum monoxide spectra in the study of laser ablation by the use of frequency-quadrupled 266 nm Nd:YAG laser radiation. Spectroscopic temperatures of 3432(35) K and 3329(13) K are obtained at a delay time of 20mu, respectively, by the use of the modified diatomic Boltzmann plot and by the use of the Nelder-Mead algorithm in the fitting of the recorded spectrum.