phenomena occur at various wavelength regions absorbed, depending
on the chemical structure; they can be observed by means of an infrared
absorption spectrophotometer.
Molecular assemblies: Orientation polarization of a dielectric possessing an
electric dipole takes place on interaction with the electromagnetic waves
in the microwave range. Moreover, as for the case of ions in a solution,
Joule heating takes place by space–charge polarization. For example, when
microwave heating an electrolyte/water solution, dielectric heating and
Joule heating occur simultaneously compared with pure water, and thus
the exothermic efficiency becomes remarkably high. Accordingly, dielectric
heating by orientation polarization of water and resistance heating by the
Joule process are enhanced in electrolyte/water media.
1.2
Microwave Heating
Microwave radiation is electromagnetic radiation spanning the frequency
range 30 GHz–300MHz (i.e., from a wavelength of 1m to 1 cm). It is used
widely in communications and in heating processes, especially in the heating of
foodstuff. Historically, the powerful interaction of microwaves with materials
was discovered in 1946 from the melting of chocolate, a process attributed to