Permanent densification of compressed silica glass: a Raman-density calibration curve

Abstract

Raman scattering experiments have been carried out to study persistent densification in SiO(2) glass following hydrostatic compression at room temperature. A new relationship linking selective Raman parameters to the degree of densification in the glass has been developed here. This approach will allow quantification of the residual densification in silica following microindentation experiments, with the goal being the development of a constitutive law for amorphous silica.

A Raman-spectroscopic study of indentation-induced structural changes in technical alkali-borosilicate glasses with varying silicate network connectivity

“…It is worthwhile to point out that the calculated pressure values show the same magnitude as those obtained from experiments on vitreous silica [8,63,64]. The data points from Refs [8,63,64] are included as hollow points in Fig. 7 for comparison.…”

“…At lower pressure values the apparent pressure derived from the experimental Raman data displays high deviations from the ideal linear correlation. The data of Deschamps [8] and Sugai [63] show similar behavior, in contrast to Polsky et al [64], which shows an almost horizontal linear behavior. We mention here the observed deviations in literature data, and especially those between 8 and 16 GPa, which could originate from the dependence of the absolute position of the Raman peak on a number of factors, e.g.…”

“…SiO 2 , soda-lime silicate and borosilicate glasses have been studied by several groups to establish calibration curves between applied pressure and the Raman spectra in order to quantify the local densification in glasses after indentation [7][8][9][60][61][62][63][64][65][66][67]. For silica glass, for example, the shift of the 430-490 cm −1 peak was correlated directly to glass densification caused by structural rearrangements as revealed by both, in-situ and ex-situ Raman measurements.…”

“…For silica glass, for example, the shift of the 430-490 cm −1 peak was correlated directly to glass densification caused by structural rearrangements as revealed by both, in-situ and ex-situ Raman measurements. In effect these studies compared thus the pressure exerted in hydrostatic and indentation experiments [8,12,18]. This approach offers subsequently the prospect to estimate from a measured Raman shift the pressure that a given material experienced during compression [59,68].…”

“…However, the prediction of the material response to deformation is a key factor in designing new compositions with improved properties. In this context, studies of vitreous silica and soda-limesilicate glasses by spectroscopic and numerical methods revealed significant structural changes under hydrostatic pressure as well as under indentation [4][5][6][7][8][9][10][11]. Structural studies on the indentation response of the important group of borosilicate glasses concentrated so far on technical low-alkaline borosilicate glasses such as the "Pyrex" or "Duran"-type glasses [12][13][14][15][16][17].…”