IR-spectroscopy for in-situ investigation of microwave processes

Summary form only given. Since the last decades microwave technology faces growing interest in various fields of materials processing. The specific benefits of microwave technology, as compared to conventional technologies for thermal processing, are the potential of a direct power deposition within the volume of dielectric materials which allows faster heating and an instantaneous control of the process. Another interesting, microwave specific feature is a selective heating. Different to a conventional process this may result in uneven or nonthermal temperature distribution on a macroscopic or microscopic scale as for example in composites if the material components are characterized by different microwave absorption behavior. Recently a novel experimental approach which may allow more detailed investigation of such uneven temperature distribution has been developed [1]. This approach makes use of an FTIR-Spectrometer in combination with a specific microwave applicator. An optimized trigger signal is used for pulse width control of the microwave process and the acquisition of IR-spectra at the same time. By this means IR- spectra were gathered during pulses as well as directly thereafter. So any difference between this IR information during microwave irradiation and without microwave irradiation can be determined. Any difference found can give information about how microwave interacts with the materials under process. Recent results will be presented.