2. A - 1 and kinetic particularities structural, thermodynamic The glassy "state",

3. SOME GLASSY COMPOSITIONS AND THEIR APPLICATIONS General Representative Applications denomination material Oxide glass SiO 2 CaO Na 2 O Window glass Oxide glass SiO 2 GeO 2 Optical fiber Organic polymer Polystyrene Structural material Chalcogenide Se ; As 2 S 3 Xerography glass IR optics Metallic glass Fe 0.8 B 0.2 Transformer cores Generally obtained by quenching from the liquid state 1 K.s < quenching rate < 10 6 K.s

7. A - 6

8. A material has a solid like behaviour for  > 10 2 s.     s    s A - 7

9. Any experiment is associated to a human observational time scale  t obs : If  t obs >>  liquid like behaviour If  t obs <<  solid like behaviour THE STRUCTURAL RELAXATION TIME A - 8

10. A - 9

11. A - 10

12. A - 11

13. A - 12

14. A - 13

15. A - 14

16. A - 15

17. A - 16

18. A - 17

19. A - 18

20. THE GLASS TRANSITION TEMPERATURE T g A - 19

21. A - 20

22. A - 21

23. A - 22

24. A - 23

25. A THERMODYNAMIC LIMIT FOR T g : THE IDEAL GLASS TRANSITION TEMPERATURE A - 24

26. THE IDEAL GLASS TRANSITION TEMPERATURE T O FROM AN ENTROPIC CYCLE A - 25

27. When cooling below Tg the difference in entropy between the glass and the crystal remains constant which leads to a residual excess entropy in the glass. A - 26

28. A - 27

29. When U or I are too small, the supercooled liquid does not crystallize (ex. : B 2 O 3, SiO 2 ) A - 28

30.  G nucleus = n B+S  G B - G L )+ n S  G S - G B )  G cr < 0  G S > 0 4/3  r 3  B  G cr + 4  r 2  S  G s A - 29

31. A - 30

32.  GLASS CERAMICS BY A CONTROLED CRYSTALLIZATION A - 31

33. Sn 2+ +h Sn 4+ +2e - 2 Cu + +2e - 2 Cu A - 32

34. A - 33

35. A - 34

36. A - 35

37. A - 36

38. A - 37

39. A - 38