Hello,

If you mean that there is no opposite peak during cooling then I see two possible reasons.

1. Some irreversible reaction occurred in your sample.

2. If you expected some kind of phase transition then absence of the opposite peak at cooling may indicate that new phase can remain in the metastable state for quite a long time and in wide temperature range.

Regards,

A. Kossoy

Dear Arcady

Thanku very much for your precious time.

For your point 1, there can be such possibility but it shouldn't.

For point 2, I don't think it can stay for long time in metastable state, because temperature is decreasing from 70 to 20 degree celcius for cooling purpose.

I am wondering for an exact method of DSC scanning, there might be an error in method I have adopted.

Regards,

Waseem

Dear Muhammad,

Judging from your experiment's description there were no visible errors - it is standard heating-cooling mode.

As far as meta stable state is concerned it may happen even in such a wide temperature diapason.

But my first question is whether we discuss the results of a single run or you checked reproducibility by running another test under the same conditions.

I always recommend not to trust the results of a single experiment - there are numerous factors that can lead to wrong results, especially when we are dealing with very small samples.

If your result is repeatable then try to use different heating rate, let's say faster one.

Good luck,

Arcady

Dear Dr. Arcady

I am very thankful to you for your great suggestions.

Regards

waseem

Waseem,

I am awfully sorry for my mistake with your name :-(