MICROCHAMBER FOR OPTICAL OBSERVATION OF FREEZE-DRYING PHENOMENA

In this paper, we describe an apparatus that allows the characterizati on of freeze-drying phenomena. For that, the sample to freeze is put i nto a microchamber where temperature and pressure are controlled. Duri ng the freeze-drying process, an optical observation of the sample is made thanks to a microscope fitted with a video camera. Images are sto red on a video band, whereas temperature and pressure are stored in a file. The connection between the kinetics of the reaction (available f rom to the video band) and the physical parameters (stored in the file ) is obtained by means of a synchronization between the storage of bot h images and the physical parameters. (C) 1997 American Institute of P hysics.