New Stable Iodide Glasses in the Cd-As-I and Cd-As-Ge-I Systems

1989 ◽  
Vol 172 ◽  
Author(s):  
Jong Heo ◽  
George H. Sigel
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Optical Fibers ◽  
Liquid Water ◽  
Infrared Region ◽  
Chemical Durability ◽  
Scanning Calorimetry ◽  
Glass Forming

AbstractIodide glasses presently being investigated suffer from their poor glass forming abilities, thermal instabilities and general lack of chemical durability. Glasses in the Cd-As-I and Cd-As-Ge-I systems are investigated in this study for the purpose of developing water-resistant, thermally stable iodide glasses and optical fibers. Differential scanning calorimetry(DSC) showed that glasses in these systems have glass transition temperature(Tg) values above 300°C. Devitrification of glasses during cooling and reheating can be suppressed by incorporating small amount of Ge atoms into ternary Cd-As-I glasses. They are transparent up to 14μm in the infrared region with excellent durability against liquid water at 90°C.

Thermal Behavior of Chalcogenide glasses Te90Se10 and Se90Te10

2015 ◽  
Vol 7 (02) ◽  
pp. 113-118
Author(s):  
Arvind Kumar Verma ◽  
Anchal Srivastava ◽  
R. K Shukla ◽  
K. C Dubey
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Glass Forming Ability ◽  
Scanning Calorimetry ◽  
Glass Forming ◽  
The Difference ◽  
Thermal Stability Of

In the present research work melt quenching method has been adopted to prepare the glassy Te-rich (Te90Se10) and Se-rich (Se90Te10 ) Chalcogenide at a pressure of 10-2 Torr with constant Temperature at 1000°C for 8 hours. Devitrification characteristics of the pure glassy Chalcogenide Te90Se10 and Se90Te90 were investigated by using Differential scanning Calorimetry (DSC) 4000 Perkin Elmer. All the measurements carried out at fixed heating rate 10 0C/min under non-isothermal conditions. The Glass transition temperature (Tg) and other thermal properties were examined by temperature modulated differential scanning Calorimetry at 40 oC to 445 oC. Glass transition temperature (Tg) represents the strength or rigidity of the glass structure. Tg affords valuable information on the thermal stability of the glassy state but Tg alone does not give any information on the glass forming tendency. The difference of the Peak crystallization temperature (Tp) and Glass transition temperature (Tg) is a strong indication of the thermal stability. The higher the value of Tc and Tg the greater is the thermal stability. Glass transition temperature (Tg=2160C) of Tellurium rich (Te90Se10) is more than Glass transition temperature (Tg=730C) of Selenium rich (Se90Te90) due to semi metallic nature of Tellurium. The difference of (Tp-Tg) is a strong indicator of both the thermal stability and Glass forming ability (GFA). Higher the value of (Tp-Tg), higher is the thermal stability and GFA because higher values of this difference indicate more kinetic resistance to the crystallization. Glass forming ability (GFA) and thermal stability of Te90Se10 is greater than Se90Te90. For memory and switching materials, glass thermal stability and GFA parameters are very important. Intensity of Se-rich (Se90Te10) is more than Te-rich (Te90Se10) and both samples are polycrystalline in nature.

scholarly journals Thermal analysis: basic concept of differential scanning calorimetry and thermogravimetry for beginners

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Nurul Fatahah Asyqin Zainal ◽  
Jean Marc Saiter ◽  
Suhaila Idayu Abdul Halim ◽  
Romain Lucas ◽  
Chin Han Chan
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Commercial Application ◽  
Scanning Calorimetry ◽  
Teaching Activities ◽  
Sample Decomposition ◽  
Calibration Baseline

AbstractWe present an overview for the basic fundamental of thermal analysis, which is applicable for educational purposes, especially for lecturers at the universities, who may refer to the articles as the references to “teach” or to “lecture” to final year project students or young researchers who are working on their postgraduate projects. Description of basic instrumentation [i.e. differential scanning calorimetry (DSC) and thermogravimetry (TGA)] covers from what we should know about the instrument, calibration, baseline and samples’ signal. We also provide the step-by-step guides for the estimation of the glass transition temperature after DSC as well as examples and exercises are included, which are applicable for teaching activities. Glass transition temperature is an important property for commercial application of a polymeric material, e.g. packaging, automotive, etc. TGA is also highlighted where the analysis gives important thermal degradation information of a material to avoid sample decomposition during the DSC measurement. The step-by-step guides of the estimation of the activation energy after TGA based on Hoffman’s Arrhenius-like relationship are also provided.

scholarly journals Physical Aging Behavior of a Glassy Polyether

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 954
Author(s):  
Xavier Monnier ◽  
Sara Marina ◽  
Xabier Lopez de Pariza ◽  
Haritz Sardón ◽  
Jaime Martin ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Physical Aging ◽  
Glassy State ◽  
Aging Behavior ◽  
Scanning Calorimetry ◽  
Narrow Temperature Range ◽  
Glass Forming ◽  
Fast Scanning Calorimetry

The present work aims to provide insights on recent findings indicating the presence of multiple equilibration mechanisms in physical aging of glasses. To this aim, we have investigated a glass forming polyether, poly(1-4 cyclohexane di-methanol) (PCDM), by following the evolution of the enthalpic state during physical aging by fast scanning calorimetry (FSC). The main results of our study indicate that physical aging persists at temperatures way below the glass transition temperature and, in a narrow temperature range, is characterized by a two steps evolution of the enthalpic state. Altogether, our results indicate that the simple old-standing view of physical aging as triggered by the α relaxation does not hold true when aging is carried out deep in the glassy state.

scholarly journals Differential Scanning Calorimetry for Determining the Thermodynamic Properties of Selected Honeys

2015 ◽  
Vol 59 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Jolanta Tomaszewska-Gras ◽  
Sławomir Bakier ◽  
Kamila Goderska ◽  
Krzysztof Mansfeld
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Thermodynamic Properties ◽  
Sugar Content ◽  
Scanning Calorimetry ◽  
Glass Transition Temperatures ◽  
Complete Liquefaction

Abstract Thermodynamic properties of selected honeys: glass transition temperature (Tg), the change in specifi c heat capacity (ΔCp), and enthalpy (ΔH) were analysed using differential scanning calorimetry (DSC) in relation to the composition i.e. water and sugar content. Glass transition temperatures (Tg) of various types of honey differed significantly (p<0.05) and ranged from -49.7°C (polyfloral) to -34.8°C (sunflower). There was a strong correlation between the Tg values and the moisture content in honey (r = -0.94). The degree of crystallisation of the honey also influenced the Tg values. It has been shown that the presence or absence of sugar crystals influenced the glass transition temperature. For the decrystallised honeys, the Tg values were 6 to 11°C lower than for the crystallised honeys. The more crystallised a honey was, the greater the temperature difference was between the decrystallised and crystallized honey. In conclusion, to obtain reliable DSC results, it is crucial to measure the glass transition after the complete liquefaction of honey.

The Glass Transition Temperature of Iron and Titanium Containing Phosphate Based Glasses

2015 ◽  
Vol 1115 ◽  
pp. 178-181
Author(s):  
S.I.S. Shaharuddin ◽  
I. Ahmed ◽  
D. Furniss ◽  
A.J. Parsons ◽  
Chris D. Rudd
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Field Strength ◽  
Ionic Radius ◽  
Phosphate Content ◽  
Scanning Calorimetry ◽  
Amorphous Nature ◽  
Glass Series

In this study various compositions in the phosphate based glass (PBG) system of (50-x)P2O5-40Ca-(5+x)Na-5TiO2 and (50-x)P2O5-40Ca-(5+x)Na-5Fe2O3, where x= 5 and 10 were investigated for glass transition temperature (Tg) via thermo mechanical analyser (TMA) and differential scanning calorimetry (DSC). The amorphous nature of the glasses was confirmed via XRD. The Tg measured via DSC was consistently higher by 19°C-29°C compared to TMA and was due to the thermal history and the heating rate of the samples. The Tg increased with increasing phosphate content in both glass systems. The Tg for Ti containing PBG was found to be in the range of 453°C-500°C whilst Tg for Fe containing PBG was in the range of 449°C-494°C. Consistently higher Tg for the Ti containing glass series compared to the Fe containing glasses may be attributed to the smaller ionic radius and therefore higher field strength of Ti4+.

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