Silica structural changes induced by thermal treatment or ionic implantation as probed by IR reflectance spectroscopy

Abstract

Fourier transformed infrared microreflectance spectroscopy is used to probe and compare the consequences of thermal quenching or ionic implantation on the structure of silica. A linear change in the main structural feature associated with Si–O–Si vibration with fictive temperature (Tf) is observed up to Tf=1400 °C. Ionic implantation is shown to shift the frequency of the main IR Si–O–Si vibration toward much lower wavenumbers, for all deposited energies, indicating that a comparison can be drawn between fictive temperature and irradiation effects. Extrapolating the linear changes in the IR structural bands obtained as a function of Tf for the implanted samples, we show that two structural (νTO) and (νB) contributions are not affected by ionic implantation, as they would be by a unique very high Tf. In the case of ionic implantation, we also evidence the development of some specific structural contributions indicating a depolymerization of silica network.

In Situ Raman Diagnostic of Structural Relaxation Times of Silica Glasses

“…For Bibent's annealing times, 7 they look also consistent with our measurements apart from the 1200°C value, which appears underestimated.…”

“…The equilibrium time needed for 1000°C for instance is about 20 days, which looks unrealistic with the needed stability of the whole Raman spectroscopy setup. Moreover, the evolution upon annealing at 1000°C is expected to be very small, as the starting T F is about 1020°C (see in Section II (1) ). The annealing times chosen by Ryu and Tomozawa 8 look to be well consistent with our relaxation time data. For Bibent's annealing times, 7 they look also consistent with our measurements apart from the 1200°C value, which appears underestimated. The relaxation times measured by Tomozawa et al 9 at 1050° and 1100°C appear somewhat lower than the present ones, by about one order of magnitude. The annealing times applied by Goller et al 10 are much lower than the relaxation times found in this paper.…”

“…These first results show for the first time a direct method to probe the structural relaxation of the glass and to evaluate its characteristic time by Raman spectroscopy. The annealing durations used here were chosen according to generally considered values, 7–9 as some exponential‐like increase of the relaxation time is expected upon decreasing the annealing temperature. In front of these results, we tried to heat a sample at 1200°C during a much longer time than those usually reported in the literature.…”

Alpha Decays Impact on Nuclear Glass Structure

“…Several studies have recently been initiated to refine the underlying analogy between the structural state created by a displacement cascade and major thermal quenching (Bureau, 2008, Bibent et al, 2009, Peuget et al, 2013. The thermal history of the glass at the core of a displacement cascade was determined by molecular dynamics calculations (Bureau, 2008).…”

Raman measurements in silica glasses irradiated with energetic ions

“…Many of the works concerning ion irradiations in silica are related to the changes induced by irradiation, namely densification effects [2], modifications in optical properties (refractive index [3], ionoluminescence [4,5], optical [6,7,8,9] and infrared [7,10,11,12,13] absorption and reflectance [14], Raman scattering [10,15,16]), mechanical properties (near-surface hardness [16,17], compaction and plastic flow [18]), chemical stability [19] and etching rate of the irradiated surfaces [1,3,6]. From these works it is concluded that microscopic and macroscopic structural modifications can both saturate at some lattice damage level depending on the density of deposited energy [3].…”