Product characterization
The following information was submitted by Dr. Harold L. Brown on Thu, 09 Apr 1998:
TherMold Partners, L.P. manufactures Thermally Stimulated Current (TSC)
spectrometers. TSC is used to perform thermal analysis of polymeric
materials by using natural or induced dipoles to probe their molecular
mobility. To analyze a material, a small sample is frozen in the
presence of a DC electric field. The electric field polarizes the
sample material and lowering the temperature increases relaxation times
so that when the field is removed, most of the polarization remains in
the sample. Reheating the material permits relaxation of polar entities
when the temperature is reached where there is sufficient energy to
allow their mobiliy. This molecular level reorientation is detected as
depolarization current by a sensitive electrometer thereby generating a
spectrum of current versus temperature. Different relaxing entities in
the material are resolved by this technique; hydroxyl groups, side
chains, etc. contribute to the spectrum at different temperatures.
Since this is a driven technique (i.e., we have control over the
polarization field which varies our return signal) Tg in lyophilized
pharmaceuticals is easy to detect and produce signal to noise ratios of
1000:1 and higher.