Showing papers by "Sumio Sakka published in 1969"
TL;DR: In this paper, the authors measured the optical absorption spectra of color centers produced in silicate glasses by γ-irradiation and found that the two color center peaks shifted toward shorter wavelengths as a result of densification of glass.
Abstract: Optical absorption spectra of color centers produced in silicate glasses by γ-irradiation were measured before and after application of pressure of 50 kbar to the glass. The two color center peaks, one found at about 400 nm and the other at about 600 nm, shifted toward shorter wavelengths as a result of densification of glass. The local shrinkages around the color centers estimated from the shifts of the peak wavelengths were much larger than the bulk shrinkages of the glasses obtained from the change in density of the glasses due to application of the pressure. Similar shifts of the color center peak wavelengths were observed also when the glass was γ-irradiated after densification. Besides the shift of the peaks, the application of the pressure caused a great increase of broad absorption through the visible region. A tentative explanation was given to this phenomenon on the basis of the formation of unknown defects due to the effect of shear accompanying the application of pressure. The annealing of the various pressure effects was also examined.
3 citations