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- ItemOD bands in the IR spectra of a deuterated soda-lime-silica glass(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2001) Peuker, Christel; Brzezinka, Klaus-Werner; Gaber, Martin; Kohl, Anka; Geißler, HeinzIR 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.
- ItemWater release behaviour of soda-lime-silica glass melts(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1995) Gaber, Martin; Harder, Ulrike; Hähnert, Manfred; Geißler, HeinzGlass with the composiüon (in mol%) 16Na₂O * 10CaO * 74SiO₂ and a water content of 0.12 to 0.005 mol/1 has been investigated by IR spectroscopy. It has been found that at a water content of < 0.01 mol/l the rado of the extincdons of the absorpdon bands at 3550 and 2800 cm⁻¹ is not constant. Through the vacuum hot extraction method it could be shown that the release of bonded water from glass melt does not occur continuously, and is not determined by the kinetics of formadon of molecular water. At concentrations > 0.01 mol/l the largest part of bonded water is released at temperatures < 1000°C. Small amounts of water can be detected at temperatures > 1250°C as well. This high-temperature release of strongly bonded water is caused by changes in the structure of glass melt or by the simultaneous release of other volatile species.
- ItemDetermination of the water content of alkali lime silica glasses by IR spectroscopy using nuclear reaction analysis for calibration(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1998) Harder, Ulrike; Geißler, Heinz; Gaber, Martin; Hähnert, Manfred; Dersch, Oliver; Rauch, FriedrichSystematic IR and NRA investigations were performed for two series of glasses with very different water contents. The glasses had the composition (in mol%): 16 R₂O · 10 CaO · 74 SiO₂ (R = sodium, potassium). The IR absorption coefTicients of the OH bands were found to be linearly correlated with the total hydrogen content obtained by the NRA measurements. Using the hydrogen concentration values from NRA, the total water contents were calculated and so-called practical IR extinction coefTicients were deduced. The values found for the soda-lime-silica glasses are 381 · mol¯¹ · cm¯¹ for the band at 3550cm¯¹ and 561 · mol¯¹ · cm¯¹ for the band at 2800cm¯¹. The values for the potassium-lime-silica glasses are 231 · mol¯¹ · cm¯¹ for the band at 3550 cm¯¹ and 78 l · mol¯¹ · cm¯¹ for the band at 2800 cm¯¹ Also, Scholze's two-band method was applied, resulting in good agreement between the water contents of the glasses derived from the IR and the NRA measurements.
- Item1H MAS NMR and IR studies on powdered alkali-lime-silica glasses(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2000) Storek, Werner; Peuker, Christel; Geißler, HeinzPowdered samples of glasses with the composition 16 R2O ∙ 10 CaO ∙ 74 SiO2 (R = Na, K, Cs) and a concentration of water in glass of about 0.03 mol ∙ l^-1 were studied by solid state 1H MAS NMR (magic angle spinning nuclear magnetic resonance). Three superimposed NMR signals at about 6.3, 12.5 and 15.6 ppm were recorded, which were assigned to three different proton sites involved in weak, strong and very strong hydrogen bonds, respectively. The relative intensity of the NMR signals depends on the type of alkali in the glass. The amount of OH groups with strong and very strong hydrogen bonding increases in relation to the weakly bonded hydroxyl groups upon substitution of Na2O, K2O or Cs2O, respectively. The result is in good agreement with the earlier IR findings for these glasses. Thus, Scholze's interpretation [1 to 3] of the region of the OH stretching vibrations in the IR spectra could be verified firstly by NMR spectroscopy as an independent analytical method.
- ItemExtinction coefficients of the OH bands in the IR spectra of basic and water-enriched silicate and aluminosilicate glasses(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2003) Peuker, Christel; Reinholz, Uwe; Jäger, Christian; Pauli, Jutta; Geißler, HeinzOH bands in the MIR and NIR spectra of selected silicate and aluminosilicate glasses were studied. The spectra of basic and water-enriched samples were compared. The ratio of the absorption coefficients of the IR bands at 3550 and 2800 cm-1 attributed to weakly and strongly hydrogen-bonded OH species, respectively, increases by more than 15 up to 70 % with water content in the glasses. These IR findings were confirmed by 1H MAS NMR measurements for a sodium calcium silicate glass. The practical extinction coefficients ε3550, pract and ε4500 increase with the water content for the alkali calcium silicate glasses as well as for the glasses with the components RO (R = Sr, Ba), AI2O3 and SiO2. For the basic glasses the values of ε3550, pract and ε4500 vary from 15 to 40 1 ∙ mol-1 ∙ cm-1 and from 0.16 to 0.41 1 ∙ mol-1 ∙ cm-1, respectively. No changes in these coefficients were found for glasses of the compositions (in mol%) 33 CaO ∙ y Al2O3 ∙ (67-y) SiO2 ( y = 5, 8, 12) with values about 60 and 0.65 1 ∙ mol-1 ∙ cm-1 for ε3550, pract and ε4500 and for bottle glasses. Furthermore, some changes were obtained in the glass network due to the hydration procedure. Α very small amount of fourfold coordinated aluminium (less than 0.3 mol% AI2O3) was found by 27Al MAS NMR measurements in a hydrated glass with the nominal composition (in mol%) 16 Na2O ∙ 10 CaO ∙ 74 SiO2. IR reflectance measurements suggest an incorporation of aluminium in the glass network for strontium aluminosilicate glasses. Thus, the increase in the practical extinction coefficients of the OH bands can be caused by an increasing water content as well as by small changes in the glass composition due to the hydration procedure. Α satisfactory agreement was found between water concentration values which were determined by NRA (nuclear reaction analysis) experiments and those which were calculated from IR measurements by the so called two-band method with composidon independent extinction coefficients for the OH bands at about 3550 and 2800 cm-1.
- ItemRecommended procedure for the IR spectroscopic determination of water in soda-lime-silica glass : Report of the International Commission on Glass (ICG) Technical Committee 14 "Gases in Glass"(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1999) Geotti-Bianchini, Franco; Geißler, Heinz; Krämer, Fritz; Smith, Ian H.The paper illustrates a procedure recommended by Technical Committee 14 (TC14 "Gases in Glass") of the International Commission on Glass (ICG) for the determination of the water content of soda-lime-silica glass by infrared transmittance spectroscopy, based on the two bands at 2.8 and 3.6 μm using as extincdon coefficients 70 and 150 l/(mol · cm), respectively As shown by the result of two intercomparisons, the agreement on the determined water concentration values can be quite satisfactory, within ±20 ppm, provided the procedure to evaluate the spectral curves is closely specified. The selected extinction coefficients are in reasonable agreement with recent evidence obtained using Nuclear Reaction Analysis.
- ItemIR and Raman study of calcium aluminosilicate glasses of the composition xCaO ∙ xAI2O3 ∙ (100 - 2x)SiO2(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2002) Peuker, Christel; Bessau, Waltraud; Brzezinka, Klaus-Werner; Kohl, Anka; Reinholz, Uwe; Geißler, HeinzVibrational 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.
- ItemIR and Raman spectroscopic study of some strontium aluminosilicate glasses(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2003) Peuker, Christel; Brzezinka, Klaus-Werner; Nofz, Marianne; Pilz, Walter; Geißler, HeinzVibrational spectra are measured for strontium aluminosilicate glasses with the composition (in mol%) x SrO ∙ y AI2O3 ∙ (100-x-y) SiO2 (33 ≤ x ≤ 40, 0 ≤ y ≤ 2) with a water content ranging from 0.014 to 0.14 mol ∙ l-1 . The OH bands systematically change with glass composition in both MIR and NIR regions. The ratio of the absorption coefficients α3550/α2800 increases with decreasing number of nonbridging oxygens per tetrahedron (NBO/T; Τ = Si, AI). This indicates an increasing amount of strongly hydrogen bonded OH groups (2800 cm-1) with NBO/T relative to the weakly bonded hydroxyls (3550 cm-1) within the compositional series. Intensity changes in the Raman and IR reflectance spectra also reflect the substitution of Al3+ for Si4+ in the network and the incorporation of Sr2+. The increasing intensity ratio of the Raman bands I945/I1070 with NBO/T indicates an increase of structural units relative to Q^3, as well as the weak shoulder at 870 cm-1 shows a rising amount of Q units. The growing intensity of the IR reflectance band at 930 cm-1 with NBO/T confirms the increasing amount of nonbridging oxygen in the glasses. Α depolarized Raman band at 330 cm-1 was assigned to an Sr-O vibration. For hydrated samples the significantly higher ratio of α3550/α2800 in relation to the basic glasses can be explained by structural changes in the samples due to the water enrichment procedure. The hydroxyl content of the basic and hydrated glasses can be estimated by the so called two-band method with composition independent extinction coefficients for the two IR bands at about 3550 and 2800 cm-1, ε3550 = 80 1 ∙ mol-1 ∙ cm-1 and ε2800 = 170 1 ∙ mol-1 ∙ cm-1, independent of the Al3+ content of the glasses.
- ItemIntercomparison of IR transmittance measurements on water-containing glasses : Report of the International Commissionon Glass (ICG) Technical Committee14 "Gases in Glass"(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2000) Geotti-Bianchini, Franco; Preo, Martina; Smith, lan H.; Nijnatten, Peter van; Geißler, Heinz; Bucher, GregΑ previous paper illustrated a procedure recommended by Technical Committee 14 (TC 14 "Gases in Glass") of the International Commission on Glass (ICG) for the determination of the water content of soda-lime-silica glasses by infrared transmittance spec-troscopy. The present paper describes the results of an intercomparison of spectral transmittance measurements performed by TC 14 in order to check the interlaboratory reproducibility that can reasonably be expected when a range of industrial laboratories determines the water content of a given sample. Three samples were circulated within a group of 10 laboratories and for each of them17 spectral transmittance curves were reported, using various spectrophotometers. From each spectrum the corresponding water content value was calculated, using the TC 14 procedure. Α statistical elaboration of the results is presented. The spectral transmittance values were affected by a significant spread, with maximum relative deviations up to 14.4 % (maximum relative standard deviation 4.5 %).The spread affecting the corresponding calculated water contents was much smaller, with maximum relative deviations within 4.8 % (maximum relative standard deviation 1.3 %).