How Differential Scanning Calorimetry (DSC) Works: Principle & Testing Guide
Differential Scanning Calorimetry (DSC) is the most widely used thermal analysis technique, measuring heat flow into or out of a sample as a function of temperature or time. DSC reveals critical thermal transitions, including melting, crystallisation, glass transition, curing, and decomposition, providing essential data for the plastics, pharmaceutical, food, chemical, and semiconductor industries. For companies seeking DSC testing at a US-based testing lab, Infinita Lab provides accredited thermal analysis through its laboratory network.
The DSC Principle
A small sample and an inert reference are heated or cooled at a controlled rate in matched furnaces. When the sample undergoes a thermal transition (melting, crystallisation, chemical reaction), it absorbs or releases heat differently from the reference. The instrument measures this differential heat flow and plots it versus temperature. Endothermic events (melting) appear as downward peaks; exothermic events (crystallisation, curing) appear as upward peaks.
Types of DSC Instruments
Heat Flux DSC
The sample and reference are heated in a single furnace platform connected by a heat-flow path. The temperature difference between the sample and reference is measured and converted to heat flow. This is the most common DSC design for routine analysis.
Power Compensation DSC
The sample and reference have separate heaters, and the instrument maintains both at the same temperature by varying the power to each heater. The power difference directly measures heat flow, providing faster response and sharper transition peaks.
Common DSC Applications
DSC applications include polymer characterisation (Tg, Tm, crystallinity per ASTM D3418), pharmaceutical purity and polymorphism screening, food quality and stability assessment, thermoset cure kinetics for composite manufacturing, and oxidative stability testing (ASTM D3895) across the plastics, pharmaceutical, and chemical industries.
Partnering with Infinita Lab for Optimal Results
Infinita Lab addresses the most frustrating pain points in the DSC Testing process: complexity, coordination, and confidentiality. Our platform is built for secure, simplified support, allowing engineering and R&D teams to focus on what matters most: innovation. From kickoff to final report, we orchestrate every detail—fast, seamlessly, and behind the scenes.
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. Request a Quote
Frequently Asked Questions (FAQs)
How does DSC work? DSC measures the differential heat flow between a sample and an inert reference as both are heated or cooled at a controlled rate. Thermal transitions in the sample cause measurable changes in heat flow.
What thermal transitions does DSC detect? DSC detects glass transition (Tg), melting (Tm), crystallization (Tc), curing exotherms, oxidation, decomposition, and polymorphic transitions with precise temperature and energy (enthalpy) values.
What ASTM standards apply to DSC testing? ASTM D3418 covers polymer transitions, ASTM E1356 covers glass transition, ASTM D3895 covers oxidative induction time, ASTM E2160 covers heat of fusion, and ISO 11357 provides general DSC methodology.
How much sample does DSC require? DSC typically requires only 5–20 mg of sample, making it suitable for small or precious specimens. The sample is placed in an aluminium or platinum pan and sealed before analysis.
Can DSC measure percent crystallinity? Yes. DSC calculates crystallinity by comparing the measured heat of fusion to the theoretical value for 100% crystalline material. This is critical for quality control of semicrystalline polymers like PE, PP, and PET.
