We report pressure (0-28 kbar) and temperature (1.1-4.3 K) dependent photon echo results for tetra-tert-butyl-terrylene (TBT) in a polyisobutylene (PIB) host. Increased pressure is found to increase the homogeneous dephasing rate over the temperature range of this study, in contrast to pressure dependent hole burning results reported for other polymer systems at somewhat higher temperatures (greater than or equal to4.2 K). A relatively small pressure increase (0 to 9 kbar) resulted in a change in the temperature dependence of the dephasing characterized by a lowering of the temperature power law exponent from similar to1.3 to similar to0.9. Further pressure increase above 9 kbar was characterized by an additional increase in the homogeneous dephasing rate without further change in the temperature exponent. The results are compared to high pressure photon echo studies of other polymer systems, and discussed in terms of the TLS (two-level-systems) model.