Radiation Effects in Glass

Probing densified silica glass structure by molecular oxygen and E’ point defect formation under irradiation

“…Those characteristics are very similar to ones evidenced by Bates et al in neutron-irradiated quartz and amorphous silica [5]. This metamict phase could be considered as a "Medium Density Amorphous" (density = 2.26 g/cm 3 ) phase in addition to the Low Density Amorphous and High Density Amorphous Phases. Hence, it presents interesting aspects regarding the still open question of polyamorphism in silica glass [6].…”

“…The densi cation of silica glass under high pressure (HP) [1], by shock waves or irradiation (laser [2], ions, electrons, neutrons) has been extensively studied. Compression of silica gives rise to permanent densi cation with a densi cation ratio of 20% (for HP > 15 GPa) while irradiation does not lead to values exceeding 3-4% [3]. We recently showed the convergence to a common "metamict-like" silica phase after irradiating with 2.5 MeV high-energy electrons amorphous silica samples having different initial densities, up to 11 GGy [4].…”

“…We recently showed the convergence to a common "metamict-like" silica phase after irradiating with 2.5 MeV high-energy electrons amorphous silica samples having different initial densities, up to 11 GGy [4]. The metamict densi ed silica phase has density of 2.26 g/cm 3 , and its structure shows a large amount of 3-membered rings, as indicated by the intense 606 cm − 1 ("D 2 ") band in the Raman spectrum [4]. Those characteristics are very similar to ones evidenced by Bates et al in neutron-irradiated quartz and amorphous silica [5].…”

“…If the interstitial voids are su ciently large, they can accommodate oxygen molecules O 2 , formed in irradiated silica glass by dimerization of two interstitial oxygen atoms created in Frenkel process [….]. Whether this process is energetically feasible, it is determined by the size of voids: O 2 easily forms by 13 MGy γirradiation in glassy silica (density 2.20 g/cm 3 ) and, in contrast, is completely absent in similarly irradiated α-quartz (density 2.65 g/cm 3 ) [9]. There is no measurable O 2 concentration in α-quartz, even after much higher (7 GGy) dose of MeV electrons [10].…”

Intrinsic Point Defects in Silica for Fiber Optics Applications

“…The integration of silica glasses in optical and electronic devices are, at present, limited by the effects of high-energy radiation on the transmission and reflection properties of the material. As reported in a large number of studies [1][2][3][4][5][6][7][8][9][10][11], the irradiation of silica with either photons or energetic particles (neutrons, electrons, protons, heavy ions) activates a wide range of damage processes that result in the formation of point defects. These localized irregularities of the network are characterized by one or more energy levels lying in the band gap of the dielectric and are responsible for the shift in the optical absorption edge of the glass to lower energies.…”