Dependencies of the total duration of the 21 μm emitting phase (t_{21 μm}). Left: Total duration of the 21 μm vs. CO-luminosity-weighted average velocity dispersion of GMCs. The color bar shows the CO luminosity-weighted average mass of GMCs. Galaxies with high surface density contrasts are identified with squares. We show in gray a linear regression fitted to the data and the gray-shaded area represents the 95% confidence interval on the regression, obtained with bootstrapping data. Right: Total duration of the 21 μm vs. the Hubble morphological type. The color bar shows the metallicity measurements for the galaxies observed with MUSE.