How to calculate glass transition temprature?

Dear all,

I would like to calculate the glass transition temperature of a polymer in Gromacs. What is the best way to calculate it? I know there is no direct way. However, I have no idea how to calculate it.

Thanks a lot

This is no a GROMACS question, but a general MD simulation question.

I would say this is practically impossible to do with MD simulations, unless the polymer is extremely short.

Hi dear Hess,

That’s right. There is no direct tool to calculate Tg. However, I used an annealing process (increasing temperature up to e.g., 1000 K then decreasing step by step back to ambient temperature). Tg will be calculated by plotting volume as a function of T. Moreover, as you said we have to use short chains.