We report on the effect of pressure on the dual segmental relaxation of an
athermal poly(isoprene-b-vinylethylene) (PI-PVE) diblock copolymer melt usi
ng dielectric spectroscopy. The quantity (partial derivative log tau/partia
l derivative P)(T) is employed as a probe of the state of dynamic miscibili
ty in the system. We find that pressure, unlike temperature, induces dynami
c homogeneity. (C) 1999 American Institute of Physics. [S0021-9606(99)52244
-7].