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Photosensitive Mechanism of Dopant‐Free, Ultraviolet‐Sensitive Calcium Aluminate Glasses
Author(s) -
HOSONO HIDEO,
YAMAZAKI KOJI,
ABE YOSHIHIRO
Publication year - 1987
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1987.tb04908.x
Subject(s) - ozonide , photosensitivity , aluminate , ultraviolet , photochemistry , dopant , doping , calcium , ultraviolet light , materials science , molecule , thermoluminescence , chemistry , optoelectronics , luminescence , organic chemistry , ozone , metallurgy , cement
Calcium aluminate glasses show high sensitivity to ultraviolet radiation without the doping of optically active components. A mechanism is proposed to account for their photosensitivity on the basis of the result that the cause of UV‐induced coloring is the emergence of two kinds of paramagnetic centers, an aluminum‐oxygen hole center (Al‐OHC) and an ozonide (O ‐ 3 ). In this model, a peroxy linkage connecting tetrahedrally coordinated Al 3+ s and a physically dissolved O 2 molecule are assumed to be present in the glasses as structural defects. On exposure to UV rays, the peroxy linkage homolvtically dissociates into a pair of A1‐OHC's by absorbing UV quanta and one of the two resulting A1‐OHC's combines with a nearby O 2 to form an ozonide. Experimental evidences substantiating the mechanism are also reported.