Glass Transition Temperature Calculator
Calculate glass transition temperature (Tg) for polymers, polymer blends, and copolymers using thermodynamic equations and empirical correlations.
Polymer Properties
Polymer Blend Mode: Calculate Tg for miscible polymer blends using Fox equation or Gordon-Taylor equation for accurate blend property prediction.
Glass transition temperature of polymer 1
Glass transition temperature of polymer 2
Fraction by weight (W₂ = 1 - W₁)
Calculation method for polymer blend Tg
Empirical parameter (typically 0.3-0.7)
Glass Transition Results
Select calculation method and parameters, then click "Calculate Tg" to see results
What Is Glass Transition Temperature?
Glass transition temperature (Tg) is the temperature range where an amorphous polymer changes from a hard, glassy state to a soft, rubbery state. This transition occurs without a change in chemical composition and is one of the most important properties in polymer science and materials engineering.
Tg determines the practical use temperature range for polymers, affects processing conditions, and influences mechanical properties. Polymers used below Tg behave like brittle glasses, while above Tg they become flexible and rubber-like.
The calculator helps predict Tg for polymer blends, copolymers, and polymers of different molecular weights using established thermodynamic and empirical equations.
How Glass Transition Temperature Is Calculated
Tg calculations use thermodynamic principles and empirical correlations based on polymer composition and molecular structure:
- Polymer blends: Fox and Gordon-Taylor equations predict Tg of miscible blends
- Copolymers: Composition-dependent equations for random and block copolymers
- Molecular weight: Empirical correlations showing Tg approaches a limiting value
These calculations are essential for polymer formulation, material selection, and processing optimization in chemical engineering and materials science.
Formula Used in the Calculator
Glass Transition Temperature Equations
Fox Equation: 1/Tg = (W₁/Tg₁) + (W₂/Tg₂)
Gordon-Taylor: Tg = (W₁·Tg₁ + k·W₂·Tg₂) / (W₁ + k·W₂)
Fox-Flory: Tg = Tg∞ - K/Mn
Where:
- W₁, W₂: Weight fractions of components
- Tg₁, Tg₂: Glass transition temperatures of pure components
- k: Gordon-Taylor empirical parameter
- Mn: Number average molecular weight
- Tg∞: Glass transition at infinite molecular weight
These equations are based on thermodynamic principles and extensive experimental data from polymer science literature.
Example Tg Calculation
Polymer Blend Analysis
| Polymer Component | Tg (°C) | Weight Fraction |
|---|---|---|
| Polystyrene (PS) | 100 | 0.6 |
| Poly(methyl methacrylate) (PMMA) | 105 | 0.4 |
| Blend Tg (Fox Equation) | 102.2 | - |
Interpretation
The 60:40 PS:PMMA blend has a predicted Tg of 102.2°C, which falls between the pure component Tg values. This intermediate Tg indicates good miscibility and single-phase behavior in the blend.
Who Can Use This Calculator?
- Polymer Chemists: Design polymer blends and predict material properties
- Materials Engineers: Select polymers for specific temperature applications
- Process Engineers: Optimize polymer processing temperatures
- Students: Learn polymer physics and thermodynamics
- Researchers: Study polymer blend behavior and phase separation
Final Thoughts
Glass transition temperature is a fundamental property that governs polymer behavior and applications. Accurate Tg prediction enables proper material selection, processing optimization, and product design in polymer engineering.
The calculator provides multiple calculation approaches to ensure accurate Tg prediction for different polymer systems, from simple blends to complex copolymer architectures.