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?