Sub-Tg relaxation in hydrous soda-lime-silicate and sodium-borosilicate glasses
- Water plays an important role for the depolymerization of silicate glasses which becomes noticeable by a distinct decrease of glass transformation temperature, Tg. Thus, it has a considerable influence on aging and fatigue as well as on sub-critical crack growth in glasses. In this connection also sub-Tg relaxation processes play a major role, but they are poorly investigated in glasses with high contents of structural bonded water. Therefore, soda-lime-silicate and sodium-borosilicate glasses with water contents up to 5 wt.% H2O were investigated by differential thermal analysis and sphere penetration viscometry, as well as internal friction measurements. The latter was applied to study network related relaxation mechanisms (α-relaxation) in the range of glass transition, as well as faster relaxation modes occurring at lower temperatures (β-, γ- relaxation). Total water content and concentrations of H2O molecules (CH2O) and OH groups (COH) in the glasses were determined by infraredWater plays an important role for the depolymerization of silicate glasses which becomes noticeable by a distinct decrease of glass transformation temperature, Tg. Thus, it has a considerable influence on aging and fatigue as well as on sub-critical crack growth in glasses. In this connection also sub-Tg relaxation processes play a major role, but they are poorly investigated in glasses with high contents of structural bonded water. Therefore, soda-lime-silicate and sodium-borosilicate glasses with water contents up to 5 wt.% H2O were investigated by differential thermal analysis and sphere penetration viscometry, as well as internal friction measurements. The latter was applied to study network related relaxation mechanisms (α-relaxation) in the range of glass transition, as well as faster relaxation modes occurring at lower temperatures (β-, γ- relaxation). Total water content and concentrations of H2O molecules (CH2O) and OH groups (COH) in the glasses were determined by infrared spectroscopy. For low water contents two sub-Tg internal friction peaks were observed and assigned to the low-temperature motion of alkali ions (γ-relaxation) and cooperative movements of dissimilar mobile species under participation of OH at higher temperature (βOH relaxation). For large water contents, where significant amounts of molecular water are evident, a low temperature shoulder appears on the β-relaxation peak. This emerging relaxation mode (βH2O relaxation) was assigned to the motions of H2O molecules.…
Autor*innen: | Stefan ReinschORCiD |
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Koautor*innen: | Ute Bauer, P. Kiefer, R. Balzer, Ralf Müller, H. Behrens, J. Deubener |
Dokumenttyp: | Vortrag |
Veröffentlichungsform: | Präsentation |
Sprache: | Englisch |
Jahr der Erstveröffentlichung: | 2017 |
DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Angewandte Physik |
Freie Schlagwörter: | Mechanical loss spectroscopy; Relaxation; Water-bearing glasses |
Veranstaltung: | 91. Glastechnische Tagung |
Veranstaltungsort: | Weimar, Germany |
Beginndatum der Veranstaltung: | 28.05.2017 |
Enddatum der Veranstaltung: | 31.05.2017 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 03.07.2017 |
Referierte Publikation: | Nein |
Eingeladener Vortrag: | Nein |