OD bands in the IR spectra of a deuterated soda-lime-silica glass

IR spectra of a deuterated glass of the composition (in mol%) 16 Na2O · 10 CaO · 74 SiO2 complete earlier spectroscopic studies on water-poor soda-lime-silica glasses. The approved IR spectroscopic method of the deuterium exchange allows a reliable assignment of the hydroxyl bands also in the case of glasses. By spectra comparison the assignment of the IR bands at 3500 and 2800 cm-1 to hydroxyl groups with different hydrogen bonding is verified. The IR band at about 4500 cm-1 is interpreted as both a combination of the stretching vibrations vO-H and vSi-OH and a combination of the stretching vibration vO-H and the deformation vibration δSiOH. The bands at 1763 and 1602 cm-1 are attributed to combination vibrations of the glass network

IR and Raman study of calcium aluminosilicate glasses of the composition xCaO ∙ xAI2O3 ∙ (100 - 2x)SiO2

Vibrational spectra are measured for calcium aluminosilicate glasses with the composition (in mol%) xCaO ∙ xAI2O3 ∙ (100 - 2x)SiO2. The OH bands show a systematic change with x in both MIR and NIR regions. The strongly asymmetric band at about 3550 cm-1 shifts to lower wave numbers with increasing x. In the same way the OH combination band at about 4500 cm-1 shifts to lower wave numbers. For the 3550 cm-1 band an extinction coefficient of about 60 1 ∙ mol-1 ∙ cm-1 is suggested for all the samples with x from 15 to 32. For the 4500 cm-1 band the extinction coefficient decreases from 1.0 to 0.49 1 ∙ mol-1 ∙ cm-1 with increasing x from 15 to 32. Systematic changes in the Raman and IR reflectance spectra reflect the substitution of Al3+ for Si4+ and a corresponding increase of Ca2+ in the network. Thus, the vibrational spectra can be related to a fully polymerized network without or with a small amount of nonbridging oxygens also for glasses with x ≥ 25

New results in Dead Sea Scrolls non-destructive characterisation. Evidence of different parchment manufacture in the fragments from Reed collection

This work presents the non-destructive spectroscopic characterisation of original Dead Sea Scrolls (DSS) parchment fragments from Ronald Reed collection. The fragments are of paramount importance because they have never been subjected to any treatment of preservation and restoration, this allows to investigate the manufacturing method of real original Jewish parchments. The manufacture of “sacred” Jewish parchments, in fact, is traditionally supposed to use a superficial tannin treatment. To study the DSS fragments, it was necessary both to analyse mock-up samples, especially manufactured in order to reproduce ancient Oriental Jewish ritual parchments, and to compare the results with those obtained in the analysis of modern and ancient Western Jewish ritual parchments, in order to test the effectiveness of the selected spectroscopic techniques. Traditionally, the main difference between Oriental and Western traditional parchment preparation consisted in the dehairing method: enzymatic for Oriental and lime-based for Western. Moreover, a finishing treatment with tannin was supposed to be applied on ritual Jewish parchments. The need of reference samples derives from the knowledge that each parchment preparation, treatment and degradation can induce structural modifications that affect the spectral features. Fourier Transform Infrared Spectroscopy by Attenuated Total Reflection (ATR-FTIR), FT-Raman and m-Raman were used in this study. The experimental results allowed us to recognise, with different sensitivity, the presence of tannin by using m-Raman and IR spectroscopies and to prove that not all the archaeological samples were manufactured in the same way with vegetal extracts. Many salts (tschermigite, dolomite, calcite, gypsum and iron carbonate) were found on the surface of DSS fragments. They can derive from the degradation processes and storage environment before the discovery or from the manufacture. Moreover, the different sensitivities and instrumental characteristics of the used techniques permitted us to establish an analytical protocol, useful for further studies of similar materials

Identification and classification of historical writing inks in spectroscopy: a methodological overview

The identification of the type of ink should be among the primary goals of manuscript description. Several techniques of instrumental analysis are available, and new tools have been appearing on the market, the main development having been to more portability and user friendliness. In this article, we would like to give an overview of several existing methods and of their respective advantages and the results (on the example of a Coptic manuscript) that can be obtained with their help