The 1700 cm
−1
bands sharply weaken and the
pure THBA bands become dominant atx≥0.8, apparently due
to a disproportionate increase of excess THBA that are not
associated with P4VP. We have also observed that at high x
(≥0.8) the samples become cloudy, indicating that THBA
macrophase separates out from P4VP and self-crystallize.