کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5441114 1510376 2017 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
On relative merits of the criteria of glass formation and effects of ultraviscous liquid properties
ترجمه فارسی عنوان
در مورد خواص نسبی معیارهای تشکیل شیشه و اثرات خواص مایع فوق العاده ذهنی
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
چکیده انگلیسی
A liquid is said to become glass when cooled to a temperature T infinitesimally below the temperature Tl → g. According to the glass-formation criteria, either, (I) τs = CI/qc at Tl → g, or, (II) (dτs/dT) ≅ CII/qc, or, (III) (τs/T) ≅ CIII/qc, where τs is taken as equal to τα, the relaxation time of the α-process, qc is the cooling rate, and CI = 16.67 K, CII ≅ 1, and CIII ≅ 1. Criterion I is generally used in glass phenomenology, criterion II was related to the effective enthalpy of activation in the Tl → g range and recommended over criterion I, and criterion III was used for discussing the pressure dependence of Tl → g. We investigate their merits by comparing formally the criteria-based τs at Tl → g in an ideal case against τα at T = Tl → g, and discuss the effects of using the glass-liquid transition temperature, Tg → l, the fictive temperature, Tf, and the midpoint temperature of the Cp-T plots as alternatives to Tl → g. The three criteria yield basically different results. Moreover, Tl → g differs from the kinetic freezing temperature of the α-relaxation process, and CI varies with both qc and the material. We suggest that contributions from several properties of ultraviscous liquids affect the shape of the Cp-T scans from which Tl → g is determined. The findings have consequences for interpretations in which τs is used as τα.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Non-Crystalline Solids - Volume 471, 1 September 2017, Pages 439-445
نویسندگان
,