Dearest sister Raghad Al-Bayatti

Alsalamo Alicom wa rahmato Allah wa barakatoh.

Have a nice time and good day.

The transmittance depends on many factors; thickness, material type, structure of the material (amorphous, poly crystalline or crystalline). aging, time of annealing temperature of annealing, photo bleaching, photo darkening  surface morphology (smoothing, roughness). ..... etc.

So the transmittance may increase or  decrease after annealing, it depends on the structure of the structure of obtained material, surface morphology and its thickness.

So you need to SEM and AFM study to identify

The two major factors that affecting the transmittance, namely, surface scattering and grain-boundary scattering (the surface morphology of the produced material. If the surface of the sample is relatively rough and its grain-boundary is irregular, the surface scattering and grain boundary scattering of sample are strong, accordingly inducing a low transmittance in the visible range. The ransmittance of the sample increases if surface roughness is decreased or the grain sizes are more uniform and grain-boundary is clear and regular. So the resultant will be increasing or decreasing of the transmittance of the sample according to the obtained result of the surface morphology.

I wish  this  is udeful and help you.

Yours

A. EL-Denglawey

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Dear Dr. Raghad 

السلام عليكم ورحمة الله 

I hope for you nice day and good times

I concur with Prof. A. Eldenglawey. But in a personal experiment on ZnSe thin films I found that:

The annealing process leads to the improvement of the crystallization of film samples, which in turn leads to the decreasing of the transmission and hence the decreasing of the refractive index of the thin-film samples of ZnSe.

The appended paper may help you in your discussion.

With my best regards

https://www.researchgate.net/publication/304150361_Study_of_optical_properties_of_thermally_evaporated_ZnSe_thin_films_annealed_at_different_pulsed_laser_powers

Article Study of optical properties of thermally evaporated ZnSe thi...

Dear Raghad

The transmittance may increase or  decrease after annealing, it depends on the structure of the structure of obtained material, surface morphology and its thickness. SO you need to another characterization like SEM AFM etc. 

Hello,

I actually work on the deposition of thin films by PECVD and I do a lot of FT-IR caracterisations on silicon (transmission mode). In fact, the amount of compound you form for the as-deposited films will remain the same after annealing (because CVD is a stable method). That's why you won't see any absorbance (or transmittance) remarkable variation. What changes is the peak shapes (they become sharper after annealing the compound).

Good luck