Raman,

I don`t know for sure but some companies state that their Raman microscopes are quite fast.

Raman is a reflection technique that allows for the placement of a mini oven under the microscope, it is fast and it can measure even a few atoms as they start to form a cluster.

I work with  infrared and it would be another option, but most machines are not fast enough.

Try refractive index. There are some very sensitive that shows a variation when nucleation occurs. Another possibilities are turbidimetry and NIR

Md,

If you are working on materials in the liquid phase I would worry about SEM and TEM with a liquid sample. As SEM is performed under high vacuum, your solution of alkane would simply be pulled off likely leaving behind a precipitate - if not pulling off your alkane entirely depending on its volatility. I think there are some insitu-TEM techniques but I do not know much about them... I think you would just need to find someone with the capabilities but as it is a newer technique that may be hard to find. . . Do you have any sort of chromophore and/or functional group on the material? Or is it just simply an alkane? I may have some thoughts using UV-vis if you have one or the other on your material.

Baillie

Dear E.P. Muniz & S. Derenzo,

Many thanks for your suggestion. Primarily I am trying to use Raman in-situ. 

Dear  Baillie, 

Thanks for your suggestion. I should think about the modification of alkane, I mean it would be better if I can add a chromophore on the alkane. Therefore, it would be possible to reveal more insight.

Best Regards-

Habib