IR-ATR investigation of surface anisotropy in silicate glasses

Vladimir Ivanovski; Thomas G Mayerhöfer; Antje Kriltz; Jürgen Popp

doi:10.1016/j.saa.2016.10.027

IR-ATR investigation of surface anisotropy in silicate glasses

Spectrochim Acta A Mol Biomol Spectrosc. 2017 Feb 15:173:608-617. doi: 10.1016/j.saa.2016.10.027. Epub 2016 Oct 17.

Authors

Vladimir Ivanovski¹, Thomas G Mayerhöfer², Antje Kriltz³, Jürgen Popp²

Affiliations

¹ Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University in Skopje, Arhimedova 5, 1000 Skopje, Republic of Macedonia. Electronic address: vladimir@pmf.ukim.mk.
² Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University, Helmholtzweg 4, Jena D-07743, Germany; Leibniz Institute of Photonic Technology (IPHT), Albert-Einstein-Str. 9, D-07745 Jena, Germany.
³ Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University, Helmholtzweg 4, Jena D-07743, Germany.

PMID: 27776315
DOI: 10.1016/j.saa.2016.10.027

Abstract

Several samples of flat soda-lime silicate glass were investigated by the Infrared Attenuated Total Reflection (IR-ATR) spectroscopy technique. The specular reflectance spectra together with the results of the performed dispersion analysis and the generated reflectance spectra, using Fresnel equations, suggest that the samples are isotropic. In contrast, spectra recorded by the ATR technique suggest an anisotropic structure on the surface of the specimen different from that in the bulk. This is established through differences in the s- and p-polarized IR-ATR spectra, which cannot be simply transformed into one another employing Fresnel formula for an isotropic case. It appears that this thin film having a structure different from the bulk is larger than the ATR effective penetration depth of the evanescent ray for each incidence angle above the critical one. The investigation suggests C₂ symmetry of the SiO₄ unit.

Keywords: IR-ATR; Silicate glass; Surface anisotropy.