It is probably one of the most accurate methods of assessing cure. By electromagnetically exciting a polymer in a specific location, one or more polarization mechanisms can be induced and the electrical properties can be easily measured. Polarization mechanisms are dependent on the chemical structure of the polymer. A potential problem with electromagnetic sensing methods is the fact that dielectric properties can change. In addition, these instabilities could change the extent of cure itself.
Temperature control presents a special problem because resin cure is usually exothermic.
However, these instabilities can be limited, at least to an extent.