in the respective crystalline phases. In addition to bands corresponding to crystalline analogs, bands associated with the presence of a large number of Si=O
multiple bonds and broken Si–O
− oxygen bridges also appear. They can be considered as a type of structural defect in comparison with the crystalline form. On the
basis of MIR spectra, the influence of alkali on lowering the degree of polymerization of a spatial silicate lattice can be followed.
In spite of the fact that in glassy spectra bands from lattice vibrations associated
with long-range order of a crystalline lattice disappear, bands indicating the presence of order in a range exceeding the scale of a single coordination polyhedron
appear in these spectra. The range 700–550 cm
−1 in infrared spectra is most often
associated with bands originating from pseudo-lattice vibrations in silicates. They
can be found in both spectra of crystalline forms, as well as in spectra of glassy
forms. They are characteristic for order larger than a molecule and indicate the
existence of so-called intermediate-range order. They mostly originate from
vibrations of ring systems present in the structure.
IR spectra can reveal the heterogeneous character of glass structure. In the case
of one-component m-SiO 2 glass, they are caused by density fluctuations resulting
from large defect concentration. Next to regions with more relaxed structure
(voids), there is also region with very compact build (large number of Si=O bonds).
In the case of multi-components glasses, IR spectra can provide information about
the existence of regions with different forms of order. This order corresponds to
phases included in their composition. Determining heterogeneity in the glass
structure is an important argument that contradicts the existence of an uninterrupted
network inside glass. At the same time, it suggests the concept of a submicroheterogeneous texture of glasses, on the basis of which lies the crystallite theory.
References
1. Görlich E (1989) Stan szklisty. Skrypt uczelniany AGH nr 1155, Kraków (in Polish)
2. Turnbull D (1969) Under what conditions can a glass be formed? Contempt Phys 10:473–488
3. Zallen R (1994) Fizyka ciał amorficznych. PWN, Warszawa (in Polish)
4. Lebedev AA (1921) The polymorphism and annealing of glass. Trans Gos Opt Inst 2:1–20
5. Zachariasen WH (1932) The atomic arrangement in glass. J Am Ceram Soc 17:3841–3857
6. Randall JT, Rooksby HP, Cooper BS (1930) The structure of glasses: the evidence of X-ray
diffraction. J Soc Glass Technol 14:219–228
7. Valenkow N, Porai-Koshitz E (1936) X-ray investigations of the glassy state. Nature
137:273–274
8. Warren BE (1933) X-ray diffraction of vitreous silica. Z Kristallogr 86:349–358
9. Warren BE (1934) X-ray determination of the structure of glass. J Am Ceram Soc 17:249–254
10. Warren BE, Krutter H, Morningstar O (1936) Fourier analysis of X-ray patterns of vitreous
SiO 2 and B 2 O 2 . J Am Ceram Soc 19:202–206
11. Wright AC, Leadbetter AL (1976) Diffraction studies of glass structure. Phys Chem Glasses
17:122–145
12. Mozzi RL, Warren BE (1969) The structure of vitreous silica. J Appl Cryst 2:164–172
15 Spectroscopic Characterization of Silicate Amorphous Materials
479
multiple bonds and broken Si–O
− oxygen bridges also appear. They can be considered as a type of structural defect in comparison with the crystalline form. On the
basis of MIR spectra, the influence of alkali on lowering the degree of polymerization of a spatial silicate lattice can be followed.
In spite of the fact that in glassy spectra bands from lattice vibrations associated
with long-range order of a crystalline lattice disappear, bands indicating the presence of order in a range exceeding the scale of a single coordination polyhedron
appear in these spectra. The range 700–550 cm
−1 in infrared spectra is most often
associated with bands originating from pseudo-lattice vibrations in silicates. They
can be found in both spectra of crystalline forms, as well as in spectra of glassy
forms. They are characteristic for order larger than a molecule and indicate the
existence of so-called intermediate-range order. They mostly originate from
vibrations of ring systems present in the structure.
IR spectra can reveal the heterogeneous character of glass structure. In the case
of one-component m-SiO 2 glass, they are caused by density fluctuations resulting
from large defect concentration. Next to regions with more relaxed structure
(voids), there is also region with very compact build (large number of Si=O bonds).
In the case of multi-components glasses, IR spectra can provide information about
the existence of regions with different forms of order. This order corresponds to
phases included in their composition. Determining heterogeneity in the glass
structure is an important argument that contradicts the existence of an uninterrupted
network inside glass. At the same time, it suggests the concept of a submicroheterogeneous texture of glasses, on the basis of which lies the crystallite theory.
References
1. Görlich E (1989) Stan szklisty. Skrypt uczelniany AGH nr 1155, Kraków (in Polish)
2. Turnbull D (1969) Under what conditions can a glass be formed? Contempt Phys 10:473–488
3. Zallen R (1994) Fizyka ciał amorficznych. PWN, Warszawa (in Polish)
4. Lebedev AA (1921) The polymorphism and annealing of glass. Trans Gos Opt Inst 2:1–20
5. Zachariasen WH (1932) The atomic arrangement in glass. J Am Ceram Soc 17:3841–3857
6. Randall JT, Rooksby HP, Cooper BS (1930) The structure of glasses: the evidence of X-ray
diffraction. J Soc Glass Technol 14:219–228
7. Valenkow N, Porai-Koshitz E (1936) X-ray investigations of the glassy state. Nature
137:273–274
8. Warren BE (1933) X-ray diffraction of vitreous silica. Z Kristallogr 86:349–358
9. Warren BE (1934) X-ray determination of the structure of glass. J Am Ceram Soc 17:249–254
10. Warren BE, Krutter H, Morningstar O (1936) Fourier analysis of X-ray patterns of vitreous
SiO 2 and B 2 O 2 . J Am Ceram Soc 19:202–206
11. Wright AC, Leadbetter AL (1976) Diffraction studies of glass structure. Phys Chem Glasses
17:122–145
12. Mozzi RL, Warren BE (1969) The structure of vitreous silica. J Appl Cryst 2:164–172
15 Spectroscopic Characterization of Silicate Amorphous Materials
479