  We present the electrodynamic response of TiOBr, which undergoes a transition
to a spin-singlet ground state for temperatures below T$_{C1}=28$ K. The
temperature evolution of the phonon anomalies indicates, like in \cl, an
extended fluctuation regime, extending well above T$_{C1}$. At low frequencies,
the spectral weight is progressively suppressed by decreasing the temperature,
suggesting the formation of a spin-gap and a considerable electron-phonon
coupling. A comparison of the two oxyhalides shows a weaker interplane coupling
and reduced dimensionality for TiOBr that enhances fluctuations and shifts the
ordering temperatures to lower values. In the fluctuation regime the
temperature dependencies of some phonon parameters track the temperature
evolution of the magnetic susceptibility.
