  We present mid-infrared (5--16micron) images and spectra of a sequence of
interacting galaxies, observed by ISOCAM. The galaxies were selected as being
at progressive stages in the time evolution of a merging event, following what
is known as Toomre's ``merger sequence'', and having no detected contribution
from an active galactic nucleus (AGN) in their mid-infrared spectrum. To trace
the intensity of the global star formation in those galaxies, we use the ratio
of the 15micron to 7micron flux. Our analysis indicates that this ratio
increases from ~1 to ~5 as galaxies move from the pre-starburst to the
merging/starburst phase only to decrease to ~1 again in the post-starburst
phase of the evolved merger remnants. Moreover, we find that the variation of
this ratio is well correlated with the one of the IRAS 25/12 and 60/100 flux
ratios. The potential to test and improve upon these results using the Infrared
Spectrograph (IRS) on board SIRTF is discussed.
