Calculator
Choose a method, enter your values, and press calculate. The result appears above this form and below the header.
Plotly Graph
The graph updates after calculation. It helps visualize blend composition, cure progression, or converted values.
Example Data Table
This example shows typical inputs for each available method.
| Method | Example Inputs | Purpose |
|---|---|---|
| Fox | Tg1 = 80 °C, Tg2 = 145 °C, w1 = 0.60, w2 = 0.40 | Estimate miscible binary blend Tg. |
| Gordon-Taylor | Tg1 = 75 °C, Tg2 = 150 °C, w1 = 0.55, w2 = 0.45, k = 0.85 | Fit asymmetric mixing behavior. |
| Copolymer | Tg1 = 95 °C, Tg2 = 130 °C, f1 = 0.70, f2 = 0.30 | Screen random copolymer composition. |
| DiBenedetto | Tg0 = -15 °C, Tg∞ = 180 °C, λ = 0.62, α = 0.78 | Track cure-dependent Tg rise. |
| Conversion | Tg = 110 °C | Convert to Kelvin and Fahrenheit. |
Formula Used
1) Fox Equation
Use Kelvin values in the equation. This method estimates the glass transition of many miscible binary blends.
2) Gordon-Taylor Equation
The constant k adjusts for unequal free-volume contributions and specific interactions between components.
3) Copolymer Rule
This form is often used for random copolymer screening when composition data is known.
4) DiBenedetto Cure Model
This relates glass transition temperature to the degree of cure for thermosetting systems.
5) Unit Conversion
Use conversion mode when you already know Tg and only need reporting in multiple units.
How to Use This Calculator
- Select the calculation method that matches your material system.
- Enter component transitions, fractions, cure values, or conversion inputs.
- Make sure fractions sum to 1.000 where required.
- Choose your preferred display unit for the main result.
- Press Calculate Tg to show the result above the form.
- Review the numeric summary, data table, and graph.
- Use CSV or PDF export for reporting and documentation.
- Compare the result against measured DSC or DMA data for validation.
Frequently Asked Questions
1) What is glass transition temperature?
Glass transition temperature is the range where an amorphous polymer changes from a hard, glassy state to a softer, rubbery state. It is not usually a sharp melting point.
2) When should I use the Fox equation?
Use the Fox equation for many miscible binary blends or random copolymer approximations when you know component glass transition values and composition fractions.
3) Why would I choose Gordon-Taylor instead?
Choose Gordon-Taylor when one component contributes differently to free volume or when experimental blend data suggests the simpler Fox relation is not accurate enough.
4) What does the constant k represent?
The constant k is an empirical interaction factor. It helps the model fit real blend behavior when component effects are not perfectly symmetric.
5) What is the DiBenedetto model used for?
It is widely used for thermosets. The model links glass transition temperature to degree of cure, making it useful in resin processing studies.
6) Should temperatures be entered in Celsius or Kelvin?
Enter temperatures in Celsius for the form. The equations internally convert values where needed, and the result is also shown in Kelvin and Fahrenheit.
7) Why does measured Tg differ from calculated Tg?
Real systems can show phase separation, plasticization, moisture effects, thermal history differences, measurement-rate effects, and composition uncertainty. These factors shift observed Tg.
8) Can this calculator replace laboratory testing?
No. It is a fast estimation and reporting tool. Use DSC, DMA, or TMA measurements to confirm the actual glass transition behavior of your material.