کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1484298 | 991628 | 2008 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Towards the origin of the memory effect in oxide glasses
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Glass samples with same composition and properties but different thermal histories can exhibit different behavior upon a subsequent heat-treatment, a phenomenon known as the memory effect. Generally, it is considered that the memory effect is due to nanoscale density fluctuation, which exists in all glasses and causes non-exponential relaxation with more than one relaxation time. Earlier, we studied the memory effect of various silica glasses and found that some pure silica glasses did not exhibit the memory effect while some silica glasses with higher impurity contents exhibited the memory effect. Based upon this finding, we suggested that the phenomenon originated from concentration fluctuation rather than density fluctuation. In this study, the memory effect in 6Â mol% K2O-94Â mol% SiO2 glass was investigated. The K2O-SiO2 glass system has a metastable immiscibility below the glass transition temperature and the chosen glass composition is the critical composition corresponding to the estimated critical temperature of the immiscibility boundary. Thus, it is expected that this glass composition would exhibit large super-critical concentration fluctuation, which increases with decreasing heat-treatment temperature. Density fluctuation, on the other hand, increases with increasing heat-treatment temperature. A much larger memory effect was observed at the lower heat-treatment temperature for the present glass. This result supports our earlier contention that the origin of the memory effect is composition fluctuation rather than density fluctuation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Non-Crystalline Solids - Volume 354, Issue 28, 15 June 2008, Pages 3246-3253
Journal: Journal of Non-Crystalline Solids - Volume 354, Issue 28, 15 June 2008, Pages 3246-3253
نویسندگان
A. Koike, M. Tomozawa,