  Recent optical conductivity measurements reveal the presence of Hubbard
excitons in certain Mott insulators. In light of these results, it is important
to revisit the dynamics of these materials to account for excitonic
correlations. We investigate time-resolved excitation and relaxation dynamics
as a function of temperature in perovskite-type LaVO${}_{3}$ thin films using
ultrafast optical pump-probe spectroscopy. LaVO${}_{3}$ undergoes a series of
phase transitions at roughly the same critical temperature $T_C\cong 140\ K$,
including a second-order magnetic phase transition (PM $\xrightarrow{}$ AFM)
and a first-order structural phase transition, accompanied by \textit{C}-type
spin order (SO) and \textit{G}-type orbital order (OO). Ultrafast optical
pump-probe spectroscopy at 1.6 eV monitors changes in the spectral weight of
the Hubbard exciton resonance which serves as a sensitive reporter of spin and
orbital fluctuation dynamics. We observe dramatic slowing down of the spin, and
orbital dynamics in the vicinity of $T_C\cong 140$ K, reminiscent of a
second-order phase transition, despite the (weakly) first-order nature of the
transition. We emphasize that since it is spectral weight changes that are
probed, the measured dynamics are not reflective of conventional exciton
generation and recombination, but are related to the dynamics of Hubbard
exciton formation in the presence of a fluctuating many-body environment.
