The spin-1 antiferromagnetic chain (or Haldane chain) is a model system which was predicted by Duncan Haldane to have gapped magnon excitations due to an underlying topological order in contrast to the gapless continuum of spinon excitations of the spin-1/2 antiferromagnetic chain. These concepts have now been well-established experimentally. Very recently theory has focused on the effects of temperature and predictions of thermally induced intraband scattering that evolves with temperature have been made. In this experiment we plan to measure the spectrum of the near-ideal spin-1 antiferromagnetic chain compound Y2BaNiO5 at several temperatures to test these predictions.