Abstract
The fictive temperature of vitreous silica containing approximately 900wtppm of hydroxyl groups was monitored with small angle x-ray scattering. The measurements were carried out during annealing and while scanning the temperature, with annealing temperatures ranging between 930 and 1330K. Fitting the data to the Adam-Gibbs-Fulcher equation by using the Tool-Narayanaswamy method yields a particularly simple thermorheological behavior for type-III vitreous silica. Unlike the general case for glass kinetics, including vitreous silica with low hydroxyl content, the relaxation time constant is nearly decoupled from the fictive temperature. This high degree of decoupling of the state of the glass and the relaxation rate agrees with the results of viscosity measurements. By improving the data analysis procedure, we have significantly increased the precision of the results, and it was possible to resolve changes of the activation energy of the relaxation processes to within 0.5%. This has made sample aging effects that had previously been undetectable visible.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.