page_title: Dynamic mechanical analysis
section_title: Measuring glass transition temperature
hierarchical_section_title: Dynamic mechanical analysis / Applications / Measuring glass transition temperature
caption_attribution_description: Deutsch: Typisches DMA Thermogramm eines amorphen Thermoplasten (Polycarbonat) gemessen im Dual Cantilever Deformationsmodus mit einer Messfrequenz von 1 Hz und einer Heizrate von 2 K/min. Die Glasübergangstemperatur, bestimmt gemäß ISO 6721-11, beträgt 151.3°C.
context_page_description: Dynamic mechanical analysis is a technique used to study and characterize materials. It is most useful for studying the viscoelastic behavior of polymers. A sinusoidal stress is applied and the strain in the material is measured, allowing one to determine the complex modulus. The temperature of the sample or the frequency of the stress are often varied, leading to variations in the complex modulus; this approach can be used to locate the glass transition temperature of the material, as well as to identify transitions corresponding to other molecular motions.
context_section_description: One important application of DMA is measurement of the glass transition temperature of polymers.  Amorphous polymers have different glass transition temperatures, above which the material will have rubbery properties instead of glassy behavior and the stiffness of the material will drop dramatically along with a reduction in its viscosity. At the glass transition, the storage modulus decreases dramatically and the loss modulus reaches a maximum. Temperature-sweeping DMA is often used to characterize the glass transition temperature of a material.
caption: Figure 2. Typical DMA thermogram of an amorphous thermoplastic (polycarbonate). Storage Modulus (E’) and Loss Modulus (E’’) and Loss Factor  tan(delta) are plotted as function of temperature.  The glass transition temperature of Polycarbonate was detected to be around 151°C (evaluation according to ISO 6721-11)
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