Visual indicator of ionizing radiation based on organic radio-and photochromic materials

The use of organic scintillators usually is based on the conversion of radiation into light and subsequent detection with photosensitive cell. Most of the instruments operating on this principle register total dose (or intensity) of the radiation regardless of its source and detection. Another method of detection is concerned with using of materials that can change their color under the radiation. They can contain compounds directly responding to the radiation (radiochromes) or responding to UV or visible light (photocromes). The last must be used in combination with corresponding scintillators producing UV irradiation. Both these ways demand new high photo- or radiosensitive substances. During the last years a series of such organic compounds has been discovered and studied. We concentrate our attention on bicyclic derivatives of aziridine 1,2,3. The photo- and radiochromic properties of bicyclic aziridines is concern with reversible ring-open process leading to bipolar structures. Our investigations showed that the induced ring-opening has two steps mechanism