De, Goutam and Kundu, Debtosh and Karmakar, Basudeb and Ganguli, Dibyendu (1993) FTIR studies of gel to glass conversion in TEOS fumed silica-derived gels. Journal of Non-Crystalline Solids, 155 (3). pp. 253-258. ISSN 0022-3093

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Hybrid gels, prepared from mixtures of tetraethyl orthosilicate (TEOS) solution and fumed silica (alkoxide:fumed silica = 1:1.25) were examined by FRIR at different stages of drying/densification up to glass formation. Transparent, bubble-free glasses containing low hydroxyl were obtained at up to 1525-degrees-C under vacuum, oxygen, carbon tetrachloride and helium atmospheres. Spectroscopic investigations revealed a free, isolated silanol stretching (nu1) band at around 3740 cm-1 split into two to three overlapping peaks after heat treatment of the gels at 600-950-degrees-C. This phenomenon is suggested to be due to either the presence of two types of isolated silanols (single and geminal) and/or an effect of the hybrid microstructure of the gels with widely varying spatial relationships among Si-OH groups, leading to closely related, weak interactions.

Item Type: Article
Subjects: Crystal Chemistry, Thermodynamics, Phase Equilibria
Divisions: Sol Gel
Depositing User: Bidhan Chaudhuri
Date Deposited: 20 Aug 2013 12:55
Last Modified: 20 Mar 2016 15:46

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