Types of Thermal Testing: DSC, TGA, TMA, DMA & More Explained
What Is Thermal Testing?
Thermal testing encompasses a broad family of analytical and performance test methods that characterise how materials, components, and systems respond to temperature — measuring thermal transitions, stability, conductivity, expansion, and degradation. It spans from sub-ambient cryogenic studies to high-temperature refractory characterisation. It is essential for material selection, product qualification, and process optimisation across the electronics, aerospace, automotive, polymer, and materials science industries.
Thermal Analysis Techniques (Material Property Characterisation)
Differential Scanning Calorimetry (DSC) — ASTM E793, ISO 11357
DSC measures heat flow into or out of a sample as a function of temperature or time. It detects and quantifies:
- Glass transition (Tg): Change in polymer chain mobility
- Melting (Tm): Crystalline phase dissolution enthalpy
- Crystallisation: Recrystallisation exotherm on cooling
- Cure enthalpy: Crosslinking exotherm in thermoset resins
- Specific heat capacity (Cp): Per ASTM E1269 using sapphire reference
- Oxidative induction time (OIT): Antioxidant effectiveness per ASTM D3895
Applications: Polymer identification, crystallinity determination, cure degree assessment, thermal stability screening.
Thermogravimetric Analysis (TGA) — ASTM E1131, ISO 11358
TGA measures mass change as a function of temperature under a defined atmosphere (inert, oxidising, or reducing). It characterises:
- Thermal decomposition temperature and kinetics
- Moisture and volatile content
- Filler and ash content (residue after combustion)
- Oxidative stability (TGA in air/oxygen)
- Dehydration of hydrated inorganic compounds
Applications: Polymer formulation analysis, additive content verification, thermal stability qualification.
Dynamic Mechanical Analysis (DMA) — ASTM E1640, ISO 6721
DMA applies an oscillating mechanical force to a specimen over a temperature range, measuring the storage modulus (E’), loss modulus (E”), and tan δ (damping). It provides:
- Glass transition temperature (Tg) from the peak in tan δ
- Frequency-dependent viscoelastic behaviour
- Cure monitoring of thermoset resins
- Low-temperature stiffness profile for engineering design
Applications: Polymer Tg determination, adhesive cure optimisation, composite structural characterisation.
Thermomechanical Analysis (TMA) — ASTM E831, ISO 11359
TMA measures dimensional change (expansion, contraction, softening) as a function of temperature under a small constant load. Provides:
- Coefficient of thermal expansion (CTE)
- Softening temperature
- Vicat softening point
- Film and fibre tension/compression behaviour
Applications: CTE matching for electronic packaging, glass and ceramic expansion, and polymer heat deformation characterisation.
Dilatometry — ISO 17562
Precision measurement of linear thermal expansion of ceramics, metals, and glass using a pushrod dilatometer. High-temperature range (up to 1700°C) accommodates refractories and ceramics.
Environmental and Performance Thermal Testing
Thermal Shock Testing — IEC 60068-2-14, ASTM E1339
Rapid transitions between extreme temperatures are used to evaluate structural integrity under thermal stress. Covered in detail in Blog 4 of this series.
Temperature Cycling — IEC 60068-2-14, JEDEC JESD22-A104
Controlled thermal cycling between defined temperature extremes with defined ramp rates and dwell times. Used for electronic component and solder joint reliability qualification.
Heat Ageing / Thermal Ageing — ASTM D573, ISO 188
Specimens were exposed to elevated temperature in a circulating air oven for defined periods. Property retention (tensile strength, hardness, elongation) after ageing characterises the thermal-oxidative durability of rubber and polymer materials.
Continuous Use Temperature (UL 746B, IEC 60216)
Electrical Relative Temperature Index (RTI) testing — materials are aged at multiple elevated temperatures, and the time to 50% property loss is determined by Arrhenius extrapolation. This determines the maximum continuous service temperature.
Flame and Fire Testing — UL 94, ISO 11925-2, ASTM E84
Flammability testing characterises how materials ignite, burn, and propagate flame — critical for electronics (UL 94), construction (ASTM E84 spread of flame), and transportation (FAR 25.853 for aircraft) applications.
Industrial Applications
In electronics, DSC characterises solder paste reflow profiles; TMA verifies CTE of PCB substrates for thermal stress analysis; DMA characterises underfill cure. In aerospace, TGA verifies the composite matrix content; DSC measures the degree of resin cure. In polymer compounding, TGA verifies filler content and decomposition temperature; DSC verifies material identity.
Conclusion
Thermal testing — encompassing analytical techniques such as DSC, TGA, DMA, and TMA, along with performance evaluations like thermal shock, cycling, ageing, and flammability testing — provides comprehensive insight into how materials and components respond to temperature-related stresses. Guided by standards such as ASTM E793, ASTM E1131, ASTM E1640, and IEC/JEDEC protocols, these methods enable accurate characterisation of thermal transitions, stability, expansion, and degradation. Selecting the appropriate combination of thermal tests based on material type, application environment, and performance requirements is essential to ensure reliability, safety, and optimal product design, making the testing strategy as important as the measured thermal properties themselves.
Why Choose Infinita Lab for Thermal Testing Services?
Infinita Lab provides the complete range of thermal analysis (DSC, TGA, DMA, TMA) and performance thermal testing (thermal shock, cycling, ageing, flammability) through our nationwide accredited thermal testing laboratory network.
Looking for a trusted partner to achieve your research goals? Schedule a meeting with us, send us a request, or call us at (888) 878-3090 to learn more about our services and how we can support you.
Frequently Asked Questions (FAQs)
What is the difference between DSC and TGA? DSC measures heat flow (energy exchange) during thermal transitions — detecting phase changes, reactions, and Tg without necessarily involving mass change. TGA measures mass change — detecting evaporation, decomposition, and combustion. They are complementary: DSC identifies thermal events; TGA quantifies mass loss associated with those events.
Which thermal technique is best for measuring the glass transition temperature (Tg) of a polymer? DMA is the most sensitive method for Tg determination — it measures the modulus drop at Tg directly. DSC detects the Cp change at Tg and is the most commonly used method due to its simplicity. TMA detects the CTE change at Tg. All three methods give slightly different Tg values due to the frequency and measurement basis differences — the method must be specified when reporting Tg.
What is the coefficient of thermal expansion (CTE) and why is it important for electronic packaging? CTE (units: ppm/°C or 10⁻⁶/°C) describes how much a material expands per degree of temperature increase. In electronic packaging, CTE mismatch between silicon die (2.6 ppm/°C), PCB substrate (14–17 ppm/°C), and solder joints drives thermomechanical fatigue during temperature cycling. CTE matching through material selection and underfill design reduces solder joint fatigue and improves reliability.
What atmosphere is used in TGA for decomposition temperature determination? Inert atmosphere (nitrogen or argon) is used to measure thermal decomposition without oxidative reactions, providing the intrinsic thermal stability. Oxidative atmosphere (air or oxygen) is used to measure thermal-oxidative stability and char/residue content after complete combustion. Both atmospheres provide complementary information.
Can thermal analysis identify unknown polymers? Yes. Combining DSC (melting temperature, Tg, crystallisation behaviour) with TGA (decomposition temperature, residue content) and FTIR spectroscopy creates a thermal fingerprint that identifies most common polymers and many blends. DSC Tm values are particularly diagnostic for semicrystalline polymers.
