Why is contact angle higher when I let the glass to be dried in silan solution?

I've read in literature that the silanization reaction is completed in a second. However, I realized an interesting thing; after one hour that my cleaned glass beads are deep coated in a silan bottle two things might happen:


1) If I take out the beads from the silan bottle and then wash them with water and then acetone, contact angle is **~102 deg** and the beads are still **transparent**.


2) But if I take out the beads and then put them on a flat surface (in one layer) and pour some silan solution on them and let them to be dried in silan, then the contact angle is **~118 deg** and glass beads are not transparent anymore (they're **milky white**).


Has anybody had a similar experience or know the reason of this?


