Glass transition and crystallization kinetic studies in Mg0.10As0.34Se0.56 chalcogenide glass by using non-isothermal techniques

Othman, A.A.; Tahon, Kh.; Osman, M.A.

doi:10.1016/s0921-4526(01)01029-8

Cited by 18 publications

(7 citation statements)

References 23 publications

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“…In comparison to benzene, cis ‐decalin and its gels showed on n value of 3 < n < 4, indicating three‐dimensional spherulitic growth units 46. The crystallization growth process depends primarily on the bulk material investigated, however, the gelator concentration appears to introduce inhomogeneity in the nucleation and distribution in crystal size 68, 69. Based on the Avrami equation and values of n , Sharples70 presented a summary table that could explain different crystallization patterns regarding their nucleation model and growth.…”

Section: Resultsmentioning

confidence: 99%

Benzene physical and chemical organogels: Effect of network scaffolding on the thermodynamic behavior of entrapped solvent molecules

Markovic¹,

Ginic‐Markovic²,

Dutta³

2004

J of Applied Polymer Sci

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This paper presents a thermodynamic investigation of the benzene physical and chemical organogels, using differential scanning calorimetry (DSC) and intends to draw an appropriate relationship between the gel network structure and the properties. Physical gels, formed by an aluminium soap of fatty acid, and chemical gels, created by in situ cross-linking of a siloxane copolymer are investigated. The effects of the type and quantity of the gelators and their corresponding network mesh size distribution in the gels on crystallization, melting, and their kinetics are examined. It appears that the kinetics of crystallization of the entrapped solvent is significantly affected by the quality of the gel network scaffolding and can be treated successfully by the Avrami equation of crystallization. From the melting behavior of the entrapped solvent crystallites, quantitative information about the number of solvent molecules bound per molecule of the gelator has been extracted. DSC proves to be a reliable technique to evaluate the population distribution of solvent molecules trapped in the physical and chemical organogel network scaffolding. The state of the solvent may be treated as a probe to understand the structure of the gels.

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Section: Resultsmentioning

confidence: 99%

Benzene physical and chemical organogels: Effect of network scaffolding on the thermodynamic behavior of entrapped solvent molecules

Markovic¹,

Ginic‐Markovic²,

Dutta³

2004

J of Applied Polymer Sci

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“…Given that the variation of 2 g ln ( ) T with β is negligibly small compared with the variation of ln ( ) β , it is possible to write [14,18]…”

Section: Glass Transitionmentioning

confidence: 99%

Glass transition and crystallization kinetics of Sb_14.5As_29.5Se_53.5Te_2.5 amorphous solid

Othman

Aly

Abousehly

2006

Physica Status Solidi (a)

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Original PaperGlass transition and crystallization kinetics of Sb 14.5 As 29.5 Se 53.5 Te 2.5 amorphous solidThe crystallization kinetics of the quaternary Sb 14.5 As 29.5 Se 53.5 Te 2.5 glassy alloy was studied under nonisothermal conditions. The method was applied to the experimental data obtained by differential scanning calorimetry (DSC), using continuous-heating techniques. In addition, two approaches are used to analyze the dependence of glass transition temperature (T g ) on the heating rate (β). One is empirical linear relationship between (T g ) and ln (β). The other approach is the use of straight line 2 g ln (T /b) vs. 1/T g for evaluation of the activation energy for glass transition. The phases at which the alloy crystallizes after the thermal process have been identified by X-ray diffraction. The diffractogram of the transformed material shows the presence of some crystallites of As, SbTe, AsSb, As 2 Se 3 , Sb 2 Se 3 and AsSe 5 Te 5 in the residual amorphous matrix.ampoule was shaken several times to maintain their uniformity. Finally, the ampoule was quenched into ice cooled water to avoid crystallization.The amorphous state of the material was confirmed by a diffractometric X-ray scan (Philips diffractometer 1710) using Cu as target and Ni as filter (λ = 1.542 Å). Energy dispersive X-ray spectroscopy (Link analytical EDS) was used to measure the elemental composition and indicates that the investigated composition is correct up to ±0.2 at%.The calorimetric measurements were carried out using differential scanning calorimeter Shimadzu 50 with an accuracy of 0.1 K, keeping a constant flow of nitrogen to extract the gases generated during the crystallization reactions, which, is a characteristic of chalcogenide materials. The calorimeter was calibrated, for each heating rate, using the well-known melting temperatures and melting enthalpies of zinc and indium supplied with the instrument [12]. 20 mg powdered samples, crimped into aluminum pans and scanned at continuous heating rates (β = 2.5, 5, 10, 15, 20, 25 and 30 K min -1 ). The value of the glass transition temperature, T g , the crystallization extrapolated onset, T c and the crystallization peak temperature, T p , were determined with accuracy ±1 K by using the microprocessor of the thermal analyzer.The fraction, χ, crystallized at a given temperature, T, is given by χ = A T /A, where A is the total area of the exotherm between the temperature, T i , where crystallization is just beginning and temperature, T f , where the crystallization is completed, A T is the area between T i and T, as shown in Fig. 1.

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“…The appeal of these methods is their simplicity and their flexibility in selection of heating (cooling) rates. The study of crystallization kinetics in amorphous materials by DSC methods has been widely discussed in the literature [8][9][10][11][12][13][14][15][16][17]. Crystallization kinetics of a-Ga 5 Sb x Se 95Àx glasses (with x = 0, 1, 5, 10) has been studied [18] by using the theory of non-isothermal transformation developed by Matusita [19].…”

Section: Introductionmentioning

confidence: 99%

Non-isothermal crystallization kinetics study on new amorphous Ga20Sb5S75 and Ga20Sb40S40 chalcogenide glasses

Othman

Amer

Osman

et al. 2005

Journal of Non-Crystalline Solids

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Glass transition and crystallization kinetic studies in Mg0.10As0.34Se0.56 chalcogenide glass by using non-isothermal techniques

Cited by 18 publications

References 23 publications

Benzene physical and chemical organogels: Effect of network scaffolding on the thermodynamic behavior of entrapped solvent molecules

Benzene physical and chemical organogels: Effect of network scaffolding on the thermodynamic behavior of entrapped solvent molecules

Glass transition and crystallization kinetics of Sb_14.5As_29.5Se_53.5Te_2.5 amorphous solid

Non-isothermal crystallization kinetics study on new amorphous Ga20Sb5S75 and Ga20Sb40S40 chalcogenide glasses

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Glass transition and crystallization kinetic studies in Mg0.10As0.34Se0.56 chalcogenide glass by using non-isothermal techniques

Cited by 18 publications

References 23 publications

Benzene physical and chemical organogels: Effect of network scaffolding on the thermodynamic behavior of entrapped solvent molecules

Benzene physical and chemical organogels: Effect of network scaffolding on the thermodynamic behavior of entrapped solvent molecules

Glass transition and crystallization kinetics of Sb14.5As29.5Se53.5Te2.5 amorphous solid

Non-isothermal crystallization kinetics study on new amorphous Ga20Sb5S75 and Ga20Sb40S40 chalcogenide glasses

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Glass transition and crystallization kinetics of Sb_14.5As_29.5Se_53.5Te_2.5 amorphous solid