While DSC measures heat flow of a sample, TMA measures the
compressibility. Below the T
g, the material behaves as a solid and
displacement of the plunger is minimal. As the sample heats up it
begins to flow and fills the voids between the particles stacked in
the compression cup.Theorydictates that volume change is closely
related to T
g and as the cup walls are of a fixed circumference, it
is important to note that the displacement measured by the TMA
instrument is directly proportional to the volume change in the
sample.Thus,inthis instance,T
g is theoreticallyrelatedtodisplacement of the plunger as well as the volume change in the sample.