We have recently shown by neutron reflectometry, that the glassy styrenic blocks, normally assumed to be impervious to aliphatic oligomers do in fact show a significant level of interaction with a model aliphatic tackifier. Although completely excluded from polystyrene at ambient temperatures, it is clear that a significant level of permeation is possible above the Tg and upon cooling to room temperature, the polystyrene remains swollen. This evidence for an unexpectedly stable nonequilibrium state is significant since the temperature cycle described is exactly that used in the applicaiton of hot melt adhesives. Here we propose to apply this test rigorously to a model polystyrene layer in contact with industrial tackifiers to elucidate a possible new mechanism behind the ageing of these materials.