Quantification of H2O contents in silicate glasses using IR spectroscopy: a calibration based on hydrous glasses analyzed by Karl-Fischer titration
Quantification of H2O contents in silicate glasses using IR spectroscopy: a calibration based on hydrous glasses analyzed by Karl-Fischer titration
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使用红外光谱法定量硅酸盐玻璃中的 H2O 含量：基于卡尔费休滴定法分析的水合玻璃的校准
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发表时间：
2003
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通讯作者：
A. Stuke
中科院分区：
文献类型：
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作者：
H. Behrens;A. Stuke
研究了含水钠钙硅玻璃（SLS）和浮法玻璃（FG）中与水有关的红外吸收带。玻璃含有0.5和6重量%之间的H2 O（对应于0.7和8摩尔/升），在铂胶囊通过重新熔化的玻璃粉，其中加入了水合成。在内部加热的气体压力容器中在1200至1250 °C的温度和100至500 MPa的压力下进行合成。通过热解和随后的卡尔-费歇尔滴定分析玻璃的总水含量（C w a t e r）。通过与含D2 O玻璃的红外光谱比较，确定了含4wt%H2O的SLS玻璃在3550，2850，2350，1730和1635 cm - 1处的5个谱带为与水有关的物种的振动模式。随着C w r的增加，3550 cm - 1处的吸收带（弱氢键水合物种的OH伸缩）相对于2850 cm - 1处的吸收带（强氢键水合物种的OH伸缩）的强度增加。因此，在3550 cm - 1处的谱带的实际吸收系数（e 3 5 5 0 p r a c t，通过将总水分配给该谱带来定义）在0.1重量%水时比在4重量%水时低20%。e 3 3 5 0 p r a c t对C w a t e r的依赖性在高于0.5 wt%时最显著，但似乎也存在于贫水玻璃中。与此相反，e2850 p r a c t并不明显依赖于水含量（FG：e 2 8 5 0 p r a c t =（40.2 ′ 2.4）l.mol - 1 .cm - 1 ; SLS：e 2 8 5 0 p r a c t =（50.8 ′ 2.0）l.mol - 1 .cm - 1，因此，优选用于浮法玻璃和钠钙硅玻璃中的水分测定。Scbolze的双带法[1]使用3550和2850 cm - 1处两个带的峰高来量化玻璃中的C w a t r也是适用于含水玻璃的第一种方法，预测水含量在20%相对范围内。然而，为了更精确地确定，必须考虑e值对C w t e r的依赖性。对1635 cm - 1处的H2 O弯曲振动带的初步评价表明，在FG和SLS玻璃中，分子H2 O是一种次要的含水物种，在总含水量为5.7wt%的FG玻璃中，分子H2 O的最大浓度为2.0wt%。在新的光谱结果和文献数据的基础上，对所谓的ABC三重态（2850，2350和1750 cm - 1带）的归属进行了讨论。
Water-related IR absorption bands were investigated in hydrous soda-lime-silica glass (SLS) and float glass (FG). Glasses containing between 0.5 and 6 wt% H 2 O (corresponding to 0.7 and 8 mol/l) were synthesized in platinum capsules by re-melting glass powder to which water had been added. Synthesis were perfomed in an internally heated gas pressure vessel at temperatures of 1200 to 1250 °C and pressures 100 to 500 MPa. The total water content (C w a t e r ) of glasses was analyzed by pyrolysis and subsequent Karl-Fischer titration. Five bands at 3550, 2850, 2350, 1730 and 1635 cm - 1 in the IR spectrum of an SLS glass containing 4 wt% H 2 O were identified as vibration modes of water-related species by comparison with a D 2 O-bearing glass. With increasing C w a t e r , the absorbance band at 3550 cm - 1 (OH stretch of weakly H-bonded hydrous species) grows in intensity relative to the band at 2850 cm - 1 (OH stretch of strongly H-bonded hydrous species). As a consequence, the practical absorption coefficient for the band at 3550 cm - 1 (e 3 5 5 0 p r a c t , defined by assigning the total water to this band) is 20% lower at 0.1 wt% water than at 4 wt% water. The dependence of e 3 3 5 0 p r a c t on C w a t e r is most pronounced above 0.5 wt% but appears to be present also in water-poor glasses. In contrast, e 2 8 5 0 p r a c t does not noticeably depend on water content (FG: e 2 8 5 0 p r a c t = (40.2 ′ 2.4) l.mol - 1 .cm - 1 ; SLS: e 2 8 5 0 p r a c t = (50.8 ′ 2.0) l.mol - 1 .cm - 1 and, hence, it is preferred for water determination in float glass and soda-lime-silica glass. Scbolze's two-band method [1] using the peak height of both bands at 3550 and 2850 cm - 1 to quantify C w a t e r in glasses is a suitable first approach also for hydrous glasses, predicting the water content within 20% relative. However, for a more precise determination the dependence of the e-values on C w a t e r has to be considered. A preliminary evaluation of the H 2 O bending vibration band at 1635 cm - 1 shows that molecular H 2 O is a minor hydrous species in FG and SLS glasses with a maximum concentration of 2.0 wt% in FG glass containing 5.7 wt% Total water. On the basis of the new spectroscopic results and data from literature the assignment of the so-called ABC triplet (bands 2850, 2350 and 1750 cm - 1 ) is discussed.