- Email: [email protected]
Lattice vibrational spectra of vitreous silica densified by pressure
Solid
State
Communications,
LATTICE
Vol.
VIBRATIONAL
11, pp. 763-765,
SPECTRA
1972.
OF VITREOUS Sho-suke
The Research
Institute
Pergamon
Printed
Press.
SILICA
DENSIFIED
in Great
Britain
BY PRESSURE
Mochizuki
for Scientific Measurement, Sendai, Miyagi, Japan
Tohoku
University
and Naoto Department
of Material Osaka
Faculty
Physics,
University,
(Received
Kawai
Toyonaka,
of Engineering Osaka,
Science,
Japan
10 June 1972 by Y. Toyozawa)
The results of the measurement of Raman scattering spectra and infra-red absorption spectra of densified vitreous silica are reported. Raman active-low frequency vibrations are largely changed by compression.
CERTAIN
vitreous
densified irradiation. towards
Bz03
however, silica with well-known the double apparatus,
To clarify approaches
silica
higher
than
this
densification
the physical properties former involves a very
mitting
oxides,
the structure. nature
than
the following
One is to investigate as a function The other is to study
on near-neighbour us with
purely
hydrostatic
is necessarily behaviour.
accompanied It is,
therefore,
cult to see whether the irreversible is due to induced shear or the real
there
the increment
of density
and
information
on non-
absorption
are many
papers
is accompanied
and broadening
there
of in which
by a decrease
frequency
and by
of all absorption that
by depends
interactions
vibrational
et al. speculated
of
the lattice
absorption
On the infra-red
glass,
stretching
hand,
bands.
is not ,only a
change of long range order of the non-crystalline structure but also a change of short range order
pressure
the pressure
solid.
the structure
can be measured
the desired
the densified
Cohen
non-crystalline
which
provides
X-ray
tool for determining
and infra-red
primarily
weakening
by a num-
approach,
On the other
structure,
scattering
of Si-0
of densified glass. The difficult problem. No one
100 kbar because
material
non-hydrostatic
of the crystal-
results
reported
us from studying silica.
vibrational
different
powerful
Unfortunately,
the densified Raman
been
l-3 In the latter
prevents
crystalline
are available.
yet produced
that
In fact, have
is the most
glasses,
polymorphic phases Furthermore, by using
the magnitude of densification of pressure and temperature.
higher
analysis
staged split sphere high pressure ’ it is possible to increase the density
of the vitreous line state.
has
ber of authors.
induced
Of these
pressure.
and interpretations
and by neutron have been made
of the vitreous
and Ge02.
has many structures.
hydrostatic
be irreversibly
the pressure
densification
as SiOn,
can
pressure’-3 many works
understanding
irreversible such
oxides
by very high 4 Recently,
the densified
vitreous
by
index-density silica, Arndt
relation of the densified vitreous et al. reported the existence of
diffi-
quasi-crystalline
trans-
densification effect of
bility
of the second
by Cohen
763
silica.
structures order
on
From the refractive
supporting
the possi-
transformation
et ~1. On the contrary,
Mackenzie
proposed asserted
VITREOUS
764
that such transformation does the densification is the shear
SILICA
DENSIFIED
the mechanism
and the property
from very high
have
investigated
been
ings
of the densification
of the densified
recovered
glass,
pressure
specimens
band
is the infra-red
infra-
1100,
spec-
the red shift
scattering
such
spectra
of the densified
and infra-red vitreous
The starting vitreous
as refractive
silica
is chemically
purity
of 99.98%
from Toshiba
Ceramic
Laser-Raman rod specimen
scattering spectra, is examinedusing
(5145 A) apparatus Model
R-750.
Industry
called
Infra-red
data,
of the 1100 cm-’
broadening
and weakening
1060 and
to be reported
which
peak
are shown appear at We can see
and the
of all the bands.
spectra
pure purchased
Co. To obtain
Japan
the
a vitreous silica argon gas laser spectroscopic,
absorption
spectra
powdered
specimens are measured 4000 cm-’ with usual double-beam the KBr pellet
Next
silica.
material with
absorption
respectively. absorption
and broaden-
of both
in Fig. 2. Absorption peaks 800 and 468 cm-’ respectively.
index,
properties,
red shift
in the peaks
in detail
of the
red absorption spectra and Raman scattering tra. In this communication, we report Raman
optical
Moreover,
can be seen
1200cm-’
( > 340 kbar)
by measurements
11, No. 6
1.53 and 1.56 respectively. The strong band (O-500 cm-‘) changed its shape conspicuously
not occur and that induced-phenomenon.
by compression. To clarify
Vol.
BY PRESSURE
of the
from 400spectrometer
using
t
I
method.
13
14
FREOUENCYkm-‘1
I
I
I
I
I2
II
IO
9
I
8 XIO'
n
(6)
F a
z t >>
b
(c)
n= t.sd
(9)
n= 1.53
(A) n= 1.46
FRuwE~Y(cm-‘l I3
I2
IO
II
9
I
0165432
FIG. 1. Raman
scattering silica at (A) n (B) n (C)n n represents the
vitreous
z4loZ
spectra of densified room temperature. = 1.46 = 1.53 = 1.56 refractive index.
In Fig.
1 there
obtained
are shown
(A) in Fig. 1 is the spectrum pression. (B) and (C) in Fig. the compressed
the Raman
from rod shaped
specimens
vitreous
scattering silica.
obtained before com1 show the spectra of
with
refractive
indices,
I
6
5
FREOUENCYkm-‘1
1
4 XIO’
FIG. 2.
Infra-red spectra in high frequency spectral region (A) and in low frequency spectral region (B) for progressively densified vitreous silica. P represent the applied pressure in kbar.
In a state easier the help
of the bond
movement of the void.
compression,
to increase banding
the actual
The decrease
atoms, Si-0-Si
of strong
for the silica
decreasing spectra
t
void
of void space
of the oxygen When such
it is much
its density
by
at the Si-O-Si space
bridg,
in the structure.
is represented
atom towards void is filled
by the
the center with
oxygen
density increases. As the result, both bending vibrational frequency (since
Vol. 11, No. 6
VITREOUS SILICA DENSIFIED BY PRESSURE
force constant for this vibration is affected as the bond angle decreases) and Si—O stretching vibrational frequency change. In the vitreous silica, the non-central force constant of Si—O stretching vibration is much smaller than that of 7 Moreover, if the tetrahedral unit central force. were compressed uniformly, then force constant of Si—O stretching vibration would increase, since the force constant is not only proportional to the bulk modulus but also is inversely proportional to the interatomic distance. Thus it is difficult to suppose that the uniform compression of the unit occur. On the other hand, uniform expansion of the unit is also unlikely to occur at high pressure. The most likely change is that which occurred in the pressure quenched silica, namely, the change of Si—O—Si bond angle. The observed decrease of the force constant on the high frequency range can, therefore, be attributed to the deformation of the tetrahedral frame-work, possible under the influence of the non-central force resulting from the surroundings.
500 cm~ band shows increment of the intensity for progressively densified vitreous silica, We attribute this change to blue shift of Si—O—Si bending and distortion modes. On the other hand, the change of high frequency Raman band indicates that the force constant of Si—O stretching vibration decreases with density. Although for infra-red absorption spectra the significant broadening and weakening of all the major bands are observed, we cannot find them on Raman scattering spectra. By considering the results, we suppose that the deformation in the Si0 4 tetrahedral unit takes place with increasing densification. Now, it is interesting to compare our vibrational spectra of densified vitreous silica with those of other silica polymorphic phases. Our Raman scattering spectra of the densified vitreous silica are similar to that of micro-crystalline glass, CER-VIT (/3-quartz like structure), ~ but our X-ray diffraction pattern of the densified vitreous silica shows no crystallization.
In the low frequency Raman scattering spectra, the intensity of continuum decreases and then the
REFERENCES 1.
BRIDGMAN P.W. and SIMON I., J. app!. Phys. 24, 405 (1953).
2.
COHEN ELM. and ROY R., Phys. Chem. Glasses. 6, 149 (1965).
3. 4. 5.
MACKENZIE J.D., J. Am. Ceram. Soc. 46, 461 (1963). 145. Butterworths, London (1960). SIMON I., ~loderrz Aspects of the Vitreous State. p. KAWAI N., MOCHIZUKI S. and FUJITA H., Phys. Lett. 34A, 107 (1971).
6.
ARNDT
7.
BELL R.j. BIRD N.E. and DEAN P., J. Phys. C. 1, 299 (1968).
8.
TOBIN MARVIN C. and BAAK TRYGGVE., J. Opt. Soc. Am. 58, 1459 (1968).
J.
765
and STOFFER., Naturwissenshaften. 55, 226 (1968).
Die Resultate der Messung des Ramanspektrums und des Irifrarotspektrums über das gedicht Quarzgläser werden gereferiert. Die Ramanaktiv Niederfrequenzschwingung werden sehr durch die Zusammenpressung ge~ndert.
State
Communications,
LATTICE
Vol.
VIBRATIONAL
11, pp. 763-765,
SPECTRA
1972.
OF VITREOUS Sho-suke
The Research
Institute
Pergamon
Printed
Press.
SILICA
DENSIFIED
in Great
Britain
BY PRESSURE
Mochizuki
for Scientific Measurement, Sendai, Miyagi, Japan
Tohoku
University
and Naoto Department
of Material Osaka
Faculty
Physics,
University,
(Received
Kawai
Toyonaka,
of Engineering Osaka,
Science,
Japan
10 June 1972 by Y. Toyozawa)
The results of the measurement of Raman scattering spectra and infra-red absorption spectra of densified vitreous silica are reported. Raman active-low frequency vibrations are largely changed by compression.
CERTAIN
vitreous
densified irradiation. towards
Bz03
however, silica with well-known the double apparatus,
To clarify approaches
silica
higher
than
this
densification
the physical properties former involves a very
mitting
oxides,
the structure. nature
than
the following
One is to investigate as a function The other is to study
on near-neighbour us with
purely
hydrostatic
is necessarily behaviour.
accompanied It is,
therefore,
cult to see whether the irreversible is due to induced shear or the real
there
the increment
of density
and
information
on non-
absorption
are many
papers
is accompanied
and broadening
there
of in which
by a decrease
frequency
and by
of all absorption that
by depends
interactions
vibrational
et al. speculated
of
the lattice
absorption
On the infra-red
glass,
stretching
hand,
bands.
is not ,only a
change of long range order of the non-crystalline structure but also a change of short range order
pressure
the pressure
solid.
the structure
can be measured
the desired
the densified
Cohen
non-crystalline
which
provides
X-ray
tool for determining
and infra-red
primarily
weakening
by a num-
approach,
On the other
structure,
scattering
of Si-0
of densified glass. The difficult problem. No one
100 kbar because
material
non-hydrostatic
of the crystal-
results
reported
us from studying silica.
vibrational
different
powerful
Unfortunately,
the densified Raman
been
l-3 In the latter
prevents
crystalline
are available.
yet produced
that
In fact, have
is the most
glasses,
polymorphic phases Furthermore, by using
the magnitude of densification of pressure and temperature.
higher
analysis
staged split sphere high pressure ’ it is possible to increase the density
of the vitreous line state.
has
ber of authors.
induced
Of these
pressure.
and interpretations
and by neutron have been made
of the vitreous
and Ge02.
has many structures.
hydrostatic
be irreversibly
the pressure
densification
as SiOn,
can
pressure’-3 many works
understanding
irreversible such
oxides
by very high 4 Recently,
the densified
vitreous
by
index-density silica, Arndt
relation of the densified vitreous et al. reported the existence of
diffi-
quasi-crystalline
trans-
densification effect of
bility
of the second
by Cohen
763
silica.
structures order
on
From the refractive
supporting
the possi-
transformation
et ~1. On the contrary,
Mackenzie
proposed asserted
VITREOUS
764
that such transformation does the densification is the shear
SILICA
DENSIFIED
the mechanism
and the property
from very high
have
investigated
been
ings
of the densification
of the densified
recovered
glass,
pressure
specimens
band
is the infra-red
infra-
1100,
spec-
the red shift
scattering
such
spectra
of the densified
and infra-red vitreous
The starting vitreous
as refractive
silica
is chemically
purity
of 99.98%
from Toshiba
Ceramic
Laser-Raman rod specimen
scattering spectra, is examinedusing
(5145 A) apparatus Model
R-750.
Industry
called
Infra-red
data,
of the 1100 cm-’
broadening
and weakening
1060 and
to be reported
which
peak
are shown appear at We can see
and the
of all the bands.
spectra
pure purchased
Co. To obtain
Japan
the
a vitreous silica argon gas laser spectroscopic,
absorption
spectra
powdered
specimens are measured 4000 cm-’ with usual double-beam the KBr pellet
Next
silica.
material with
absorption
respectively. absorption
and broaden-
of both
in Fig. 2. Absorption peaks 800 and 468 cm-’ respectively.
index,
properties,
red shift
in the peaks
in detail
of the
red absorption spectra and Raman scattering tra. In this communication, we report Raman
optical
Moreover,
can be seen
1200cm-’
( > 340 kbar)
by measurements
11, No. 6
1.53 and 1.56 respectively. The strong band (O-500 cm-‘) changed its shape conspicuously
not occur and that induced-phenomenon.
by compression. To clarify
Vol.
BY PRESSURE
of the
from 400spectrometer
using
t
I
method.
13
14
FREOUENCYkm-‘1
I
I
I
I
I2
II
IO
9
I
8 XIO'
n
(6)
F a
z t >>
b
(c)
n= t.sd
(9)
n= 1.53
(A) n= 1.46
FRuwE~Y(cm-‘l I3
I2
IO
II
9
I
0165432
FIG. 1. Raman
scattering silica at (A) n (B) n (C)n n represents the
vitreous
z4loZ
spectra of densified room temperature. = 1.46 = 1.53 = 1.56 refractive index.
In Fig.
1 there
obtained
are shown
(A) in Fig. 1 is the spectrum pression. (B) and (C) in Fig. the compressed
the Raman
from rod shaped
specimens
vitreous
scattering silica.
obtained before com1 show the spectra of
with
refractive
indices,
I
6
5
FREOUENCYkm-‘1
1
4 XIO’
FIG. 2.
Infra-red spectra in high frequency spectral region (A) and in low frequency spectral region (B) for progressively densified vitreous silica. P represent the applied pressure in kbar.
In a state easier the help
of the bond
movement of the void.
compression,
to increase banding
the actual
The decrease
atoms, Si-0-Si
of strong
for the silica
decreasing spectra
t
void
of void space
of the oxygen When such
it is much
its density
by
at the Si-O-Si space
bridg,
in the structure.
is represented
atom towards void is filled
by the
the center with
oxygen
density increases. As the result, both bending vibrational frequency (since
Vol. 11, No. 6
VITREOUS SILICA DENSIFIED BY PRESSURE
force constant for this vibration is affected as the bond angle decreases) and Si—O stretching vibrational frequency change. In the vitreous silica, the non-central force constant of Si—O stretching vibration is much smaller than that of 7 Moreover, if the tetrahedral unit central force. were compressed uniformly, then force constant of Si—O stretching vibration would increase, since the force constant is not only proportional to the bulk modulus but also is inversely proportional to the interatomic distance. Thus it is difficult to suppose that the uniform compression of the unit occur. On the other hand, uniform expansion of the unit is also unlikely to occur at high pressure. The most likely change is that which occurred in the pressure quenched silica, namely, the change of Si—O—Si bond angle. The observed decrease of the force constant on the high frequency range can, therefore, be attributed to the deformation of the tetrahedral frame-work, possible under the influence of the non-central force resulting from the surroundings.
500 cm~ band shows increment of the intensity for progressively densified vitreous silica, We attribute this change to blue shift of Si—O—Si bending and distortion modes. On the other hand, the change of high frequency Raman band indicates that the force constant of Si—O stretching vibration decreases with density. Although for infra-red absorption spectra the significant broadening and weakening of all the major bands are observed, we cannot find them on Raman scattering spectra. By considering the results, we suppose that the deformation in the Si0 4 tetrahedral unit takes place with increasing densification. Now, it is interesting to compare our vibrational spectra of densified vitreous silica with those of other silica polymorphic phases. Our Raman scattering spectra of the densified vitreous silica are similar to that of micro-crystalline glass, CER-VIT (/3-quartz like structure), ~ but our X-ray diffraction pattern of the densified vitreous silica shows no crystallization.
In the low frequency Raman scattering spectra, the intensity of continuum decreases and then the
REFERENCES 1.
BRIDGMAN P.W. and SIMON I., J. app!. Phys. 24, 405 (1953).
2.
COHEN ELM. and ROY R., Phys. Chem. Glasses. 6, 149 (1965).
3. 4. 5.
MACKENZIE J.D., J. Am. Ceram. Soc. 46, 461 (1963). 145. Butterworths, London (1960). SIMON I., ~loderrz Aspects of the Vitreous State. p. KAWAI N., MOCHIZUKI S. and FUJITA H., Phys. Lett. 34A, 107 (1971).
6.
ARNDT
7.
BELL R.j. BIRD N.E. and DEAN P., J. Phys. C. 1, 299 (1968).
8.
TOBIN MARVIN C. and BAAK TRYGGVE., J. Opt. Soc. Am. 58, 1459 (1968).
J.
765
and STOFFER., Naturwissenshaften. 55, 226 (1968).
Die Resultate der Messung des Ramanspektrums und des Irifrarotspektrums über das gedicht Quarzgläser werden gereferiert. Die Ramanaktiv Niederfrequenzschwingung werden sehr durch die Zusammenpressung ge~ndert.