  Following a series of similar calculations in simpler non-conformal
holographic setups, we determine the quasinormal mode spectrum for an operator
dual to a gauge-invariant scalar field within the Improved Holographic QCD
framework. At temperatures somewhat above the critical temperature of the
deconfinement transition, we find a small number of clearly separated modes
followed by a branch-cut-like structure parallel to the real axis, the presence
of which is linked to the form of the IHQCD potential employed. The temperature
dependence of the lowest nonzero mode is furthermore used to study the
thermalization time of the corresponding correlator, which is found to be of
the order of the inverse critical temperature near the phase transition and
decrease slightly faster than $1/T$ at higher temperatures.
