Analysis of soda-lime glasses using non-negative matrix factor deconvolution of Raman spectra

Abstract

Novel statistical analysis and machine learning algorithms are proposed for the deconvolution and interpretation of Raman spectra of silicate glasses in the Na 2 O-CaO-SiO 2 system. Raman spectra are acquired along diffusion profiles of three pairs of glasses centered around an average composition of 69.9 wt.% SiO 2 , 12.7 wt.% CaO, 16.8 wt.% Na 2 O. The shape changes of the Raman spectra across the compositional domain are analyzed using a combination of principal component analysis (PCA) and sparse non-negative matrix factorization (NMF). This procedure yields components accounting for the observed changes, as well as their mixing proportions, without any direct prior assumption as to their actual shape, number or position. These methods are applied separately to the Q band (wavenumbers in the range 850-1400 cm −1), the main band (200-850 cm −1) and to the whole spectra (200-1400 cm −1). Compositional profiles obtained by Electron Probe Micro-Analysis (EPMA) are then used to relate spectral components to structural entities. Spectral components extracted from a Q band analysis and a complete spectral analysis show significant similarities both in terms of shape of the components and their mixing proportions. This result implies a link between Q n species and the shift of the medium-range network features in the main band of the Raman spectra. To illustrate the possibilities of the method, a linear regression model is used to relate the proportions of spectral components derived from the Raman spectra to chemical composition. This model can be used to determine the composition of different glasses inside the investigated compositional domain with reasonable accuracy.

Effects of d0 and s2 cations on optical properties of silicate glasses

“…[NbO6] octahedra have high Raman cross sections and the peak at 875 cm -1 is detectable at low (>0.10mol%) concentrations in SLS glasses [263,264] and is present in Figure 57, Figure 58 and Figure 59. Deconvolution of Nb2O5 spectra along with base SLS through the program FitYK shown in Figure 61, give a BO:NBO ratio of circa 64:36 indicating high polymerisation and non-significant changes to the polymerisation with the incorporation of 0.20mol% Nb2O5 and are consistent with other similar glasses [262]. Molybdate tetrahedra likewise present strong Raman cross sections, thus giving rise to a stronger signal relative to the corresponding network [265] demonstrated in Figure 57.…”

“…Raman spectra of base and doped glasses are shown in Figure 57. Each trace is composed of five main peaks, consistent with other float and soda lime silica systems [261,262]. Samples doped with Nb2O5 and MoO3 have an additional peak highlighted by…”

Optical Spectroscopy of Crystal Nucleation One Nucleus at a Time

“…2). 37 NMF has been used to deconvolute spectra in the field of Raman spectroscopy, and a powerful aspect of this analysis algorithm is that a set of partial Raman spectrum (PRS) as well as the amplitude of each PRS during the spectral evolution can be obtained without any assumption concerning the spectral shapes. The number of PRS used for the deconvolution is the only predetermined parameter.…”

High‐sensitivity Raman imaging of the surface of casted glass plates

“…This procedure consistently yielded clear, bubble‐free, and visually homogeneous glass plates (Figure 1). The chemical homogeneity of samples synthesized by this procedure was assessed by electron microprobe analysis (EMPA) in a prior study on samples of similar volume and compositions, which showed to be homogeneous with standard deviations below 0.02 wt% [14] . For the sake of simplicity, this paper will highlight results from a sample that is at the center of the composition range.…”