(a) Comparison of the transient photoproduct spectrum at Tw values of 1.5, 2.0, 3.0, and 5.0 ps (circles) to the linear temperature difference spectrum (solid curve). The differences for Tw < 5 ps demonstrate that, following vibrational relaxation and subsequent hydrogen bond breaking, the hydrogen bond distribution is initially not thermally equilibrated. (b) Full photoproduct spectral evolution obtained from subtraction of the decaying reactant spectrum. The photoproduct spectrum starts to grow in at ~1 ps after the excitation of the hydroxyl stretch vibration and becomes constant after ~5 ps.