Structure and properties of glasses andmelts in the MgO-Al2O3-SiO2,
CaO-Al2O3-SiO2 ,MgO-CaO-Al2O3-SiO2 systems
Daniel R. Neuville Cormier L. 2, de Ligny D.3, Flank A-M. 4, Henderson G.S. 5,
Lagarde P.4, Massiot D.6, Millot F.6, Montouillout V.6, Rifflet J.C.6, Richet P. 1, Roux J.1
1 Physique des Minéraux et des Magmas, IPGP-CNRS, 4 place Jussieu, 75252 Paris2IMPMC, Universités PARIS 6 et 7, CNRS, 4 place Jussieu, 75252 Paris
3LPCML, Université Lyon 1, CNRS UMR 5620, 12 rue Ampère, 69622 Villeurbanne4 SOLEIL L'Orme des Merisiers, BP48, 91192 Gif s/Yvette, France.
5Dept of Geology, University of Toronto, 22 Russell St, Toronto, Canada6 CRMHT-CNRS, 1D av. Recherche Scientifique, 45071 Orléans cedex 2, France
0 20 40 60 80 100
SiO2
Basalte
Téphrite
Péridotite
Dunite
Phonolite
Andésite
Trachyte
Rhyolite
Al2O3 FeO MgO CaO
Na2O K2O
TiO2
MO
1st Networkformer
2sdNetworkformer
1) MAS System
Richet et al.
2) CAS System
Richet et al.
3) CMAS System
1
3
5
7
9
11
13
15
5 6 7 8 9 10 11 12 13
104/T (K-1)
Vis
co
sity
(lo
g P
ois
e)
Couette apparatus
High temperature
Low temperature
Creep apparatus!
" =#
3˙ $
Viscosity measurements
Neuville, 2006
Viscosity measurements
1
3
5
7
9
11
13
15
5 6 7 8 9 10 11 12 13
104/T (K-1)
Vis
co
sity
(lo
g P
ois
e)
Tg => η = 1013 Poise
Creep apparatusNeuville and Richet (1991)
±0.02
Rotatory viscometerNeuville (1992)
±0.04
NBS710
10.5
11
11.5
12
12.5
13
6 7 8 9
Vis
cosi
ty (
log P
ois
e)
Stress (log Nm-2)
836 K842 K
853 K
864 K
Webb and Dingwell, 1991838 K
Neuville, Chem. Geol. 2006
MAx.y
x=%SiO2
y=%Al2O3
Mole%
SiO2
Al2O3MgO
MA63.18
MA50.25
MA55.22
MA72.14
MA76.11
MA60.10
MA50.00
MA57.11
MA48.13
MA53.12
MA42.14
5050
50
MA76.17
MA50.30
MA50.35 MA50.40
MA48.03
MAS
Normal quentch
Rapid quentch
20
22
24
26
28
30
0 20 40 60 80 100
Seifert et al. (1/1)
R=1
R=3
Mole % SiO2
Mola
r v
olu
me (
cm
3)
MV of glass increaseslinearly with SiO2
and decreases with MgO
Cpconf = Cp
l - Cpg(Tg)
Tg => log η = 13 log Po
After Richet (1987)and Richet and Bottinga (1984)
Configurational heat capacityincreases with decreasing SiO2and increasing Al2O3 content. 8
12
16
20
24
28
0 20 40 60 80 100
R=1
R=3
Mole % SiO2
Cp
con
f (T
g)
(J/m
ol
K)
MASR=MgO/Al2O3
-1
1
3
5
7
9
11
13
5 6 7 8 9 10
M76.11
M63.18
Mg55.22
Mg50.25
104/T (K-1)
Vis
cosi
ty (
log P
ois
e)
Viscosity increases strongly with SiO2
1000
1100
1200
1300
1400
1500
0 20 40 60 80 100
R=1R=3
Mole % SiO2
Tg
(K
)
?
Tg increases stronglywith SiO2
and very small variationbetween 50 and 70 mole
% of SiO2
?
Viscosity MAS
Q4 (Si or Al)
Q3 (Si or Al)
Q2 (Si or Al)
Qn speciesQ: (Si,Al) with 4 O n: number of bridging oxygen
Raman spectroscopy
0
40
80
120
160
200 400 600 800 1000 1200
Inte
nsi
ty (
a.u
.)
Wavenumber (cm-1)
MA60.10
MA42.14
MA48.13
MA57.11
MA53.12
R=MgO/Al2O3=3
Fig. 2b
0
40
80
120
160
200 400 600 800 1000 1200
Inte
nsi
ty (
a.u
.)
Wavenumber (cm-1)
MA76.11
MA50.25
MA55.22
MA72.13MA63.18
R=MgO/Al2O3=1
Fig. 2a
15
10
5
0
Am
plit
ud
e
120011001000900
Wavelength,
-4
0
4
Re
sid
ua
ls
currentpeak
Ca76.11 89.1962 Peak#1: position= 1060.42+/-137.64, area= 2406.13+/-1996.94, width (fwhm)= 175.345+/-72.5931 Peak#2: position= 1151.58+/-37.6097, area= 1071.84+/-2147.6, width (fwhm)= 134.965+/-31.9661 Peak#3: position= 975.436+/-44.7186, area= 688.072+/-2763.76, width (fwhm)= 128.558+/-63.6015
Raman spectroscopy MAS
800
900
1000
1100
1200
0 20 40 60 80 100
Mole % SiO2
Wa
ve
nu
mb
er
(cm
-1)
120
MA42.14
(ppm)120 80 40 0
100
80
60
40
20 MA48.03
(ppm)120 80 40 0
100
80
60
40
20MA48.13
120 80 40 0
100
80
60
40
20
(ppm)
MA57.11
(ppm)120 80 40 0
100
80
60
40
20MA54.18
(ppm)120 80 40 0
100
80
60
40
20MA53.12
(ppm)80 40 0
100
80
60
40
20MA60.10
(ppm)120 80 40 0
100
80
60
40
20
27Al NMR MAS
MA76.11
(ppm)120 80 40 0
100
80
60
40
20MA72.13
100
120 (ppm)80 40 0
80
60
40
20
120 120
100
MA63.18
(ppm)120 80 40 0
80
60
40
20MA55.22
100
80
60
40
20
(ppm)80 40 0
MA50.25
80 40 0
100
80
60
40
20
(ppm)80 40 0
80
60
40
20
120
MA50.30
(ppm)120 80 40 0
80
60
40
20MA50.35
(ppm)120 80 40 0
80
60
40
20MA50.40
(ppm)120 80 40 0
80
60
40
20MA76.17
27Al NMR MAS
Mg - Conclusions
• MV increases and Cpconf decreases with SiO2
• NMR => VAl increases with Al2O3
• Viscosity and Raman spectroscopy for R=1 glasses =>random substitution Si/Al, few structural changes
• Viscosity and Tg increase with SiO2 and Al2O3
MAS
1996 K1996 K
2293 K2293 K
2843 K2843 K
R = CaO/AlR = CaO/Al22OO33
R = 1R = 1
R = 1.5R = 1.5
R = 3R = 3
Diagram Diagram in in weight weight %%From RankinFrom Rankin, 1915, 1915
Cax.yx=%SiO 2y=%Al 2O3Mole%
SiO 2
Al2 O3CaO
Ca63.18
Ca50.25
Ca58.20
Ca70.15
Ca33.33
Ca29.36
Ca19.40
Ca76.11Ca77.07
Ca68.08
Ca60.10
Ca55.18
Ca50.12Ca50.00
Ca48.03
Ca44.11Ca46.07
Ca42.14
Ca39.22
Ca33.18Ca32.17
Ca38.15Ca35.27
Ca23.21Ca20.31
Ca12.44
Ca10.35
Ca16.21
Ca10.23
Ca0.50
5050
50
Ca0.39
Ca0.45
Ca0 .3 0
C3A= Ca0 .25
C 12A 7= Ca 0. 36
CA= Ca 0. 50
C A2=Ca0 .66
C A6= Ca 0.8 6
Ca76.17
Ca50.30
Ca50.35
Ca33.43
Ca33.38
Ca10.50
Ca10.55
Normal quentch
Rapid quentch
CAS
MV of glass increaseswith SiO2
and decreases with CaO
Cpconf = Cp
l - Cpg(Tg)
Tg => log η = 13 log Po
After Richet (1987)and Richet and Bottinga (1984)
0
5
10
15
20
25
30
35
40
0 20 40 60 80 100
R = 1R = 3R = 1.5
Mole % SiO2
Cp
co
nf (
Tg)
(J/m
ol)
R = CaO/Al2O3
Configurational heat capacityincreases with decreasing SiO2and increasing Al2O3 content.
CAS
22.5
23.5
24.5
25.5
26.5
27.5
0 20 40 60 80 100
Seifert et al. (1/1)
R=1
R=3
Mole % SiO2
Mola
r v
olu
me (
cm
3)
Viscosity as a function of SiO2 for 3 joins1<R=CaO/Al2O3 <3
Decrease of viscosity from R=1 to R=3
Viscosity decreases with decreasing SiO2and increasing CaO
0
2
4
6
8
10
12
14
0 20 40 60 80 100
Mole % SiO2
Vis
cosi
ty (
log
po
ise)
1900 K
1700 K
1150 K
1175 K
1200 K
R=1
0
2
4
6
8
10
12
14
0 20 40 60 80 100
1175 K
Mole % SiO2
1150 K
1125 K
1700 K
1900 K
R=1.5
0
2
4
6
8
10
12
14
0 20 40 60 80 100
Mole % SiO2
1900 K
1700 K
1100 K
1075 K
1050 K
R=3
Increase of viscosity at low SiO2
CAS
Neuville, 1992
Glass transition temperature
Tg => η = 1013 poise
Neuville, 1992, from viscosity
R=CaO/Al2O3
Tg = 1400 KSiO2 glass
Tg decrease with SiO2
CAS
1000
1050
1100
1150
1200R=1
R=3
R=1.57
R=1.34
R=1.5
R=2
0 20 40 60 80 100Mole % SiO2
Tg
(K)
Higby et al.,à partir de DTA
Neuville, à partir des viscosités
maximum in Tg at 10-20 mol% SiO2Neuville et al. Chem. Geol., 2004, 213,153Neuville, 1992
0
2
4
6
8
10
12
14
0 20 40 60 80 100
Mole % SiO2
Vis
cosi
ty (
log
po
ise)
1900 K
1700 K
1150 K
1175 K
1200 K
R = 1
R = CaO/Al2O3
log η = Ae + Be/TSconf (T)Sconf(Tg) = Smix+ ΣxiSi
conf (Tg) Sconftop = ΣxiSi
conf (Tg).
Smix = - nR Xi ln XiXi=Al/(Al+Si)
Ideal mixing => random distribution
with Cpconf = Cp
l - Cpg(Tg)
Sconf(T) = Sconf(Tg) +
Configuration Entropy
Substitution of Si by Al in Q4 species along the join R=1
CAS
SiO2 Tg=1400K
Cax.yx=%SiO
2y=%Al 2O 3Mole%
SiO 2
Al 2 O 3CaO
Ca63.18
Ca50.25
Ca58.20
Ca70.15
Ca33.33
Ca29.36
Ca19.40
Ca76.11Ca77.07
Ca68.08
Ca60.10
Ca55.18
Ca50.12Ca50.00
Ca48.03
Ca44.11
Ca46.07
Ca42.14
Ca39.22
Ca33.18
Ca32.17
Ca38.15
Ca35.27
Ca23.21
Ca20.31
Ca12.44
Ca10.35
Ca16.21
Ca10.23
Ca0.50
5050
50
Ca0.39
Ca0.45
Ca0.30
C 3A=Ca 0
.25
C12A
7=Ca0. 36
CA=C a0
.50
CA2 =
Ca 0.6
6
CA6=Ca0
.86
Ca76.17
Ca50.30
Ca50.35
Ca33.43
Ca33.38
Ca10.50
Ca10.55
Ca50..40
Ca33..50
900
1000
1100
1200
1300
1400
0 20 40 60 80 100
Mole % SiO2
Tg (
K)
SiO2 => Tetrahedra SiO4CaAl2O4 => Tetrahedra AlO4
substitution of 1 Si by 1 Al andCa charge compensator
CaAl2O4 SiO2
CAS
Anomaly ?
0
50
100
150
200
250
300
200 400 600 800 1000 1200 1400
Inte
nsi
ty, a.u
.
Wavenumber, cm-1
Ca12.44
Ca19.40
Ca29.36
Ca33.33
Ca50.25
Ca63.18
Ca70.15
Ca76.11
R=CaO/Al2O
3=1
15
10
5
0
Am
plit
ud
e
120011001000900
Wavelength,
-4
0
4
Re
sid
ua
ls
currentpeak
Ca76.11 89.1962 Peak#1: position= 1060.42+/-137.64, area= 2406.13+/-1996.94, width (fwhm)= 175.345+/-72.5931 Peak#2: position= 1151.58+/-37.6097, area= 1071.84+/-2147.6, width (fwhm)= 134.965+/-31.9661 Peak#3: position= 975.436+/-44.7186, area= 688.072+/-2763.76, width (fwhm)= 128.558+/-63.6015
SiO2
CaO Al2O3
CAS
Neuville et al. GCA, 2004, 68, 5071
Al substitutes Si in Q4
=> 890 cm-1 Al inQ4
700
800
900
1000
1100
1200
0 20 40 60 80 100
Mole % SiO2
Wa
ven
um
ber,
cm
-1
R=CaO/Al2O3=1
Si (Q4 )T (Q4 )
T (Q4 )
1050 cm- 1
Al (Q3 ?)
Decresase ofwavenumbers with SiO2
CAS
Neuville et al. GCA, 2004, 68, 5071, Neuville et al. Chem Geol., 2006, 229, 173
(ppm)-60-40-20020406080100120
Exp.Model
CA 50.30
R=CaO/Al2O3=1 + Al2O3 ex(ppm)
CA 50.25
-60-40-20020406080100120
Exp.Model
7%AlO5
84%AlO4
14%AlO5
2%AlO6
RMN 750MHz, CRMHT, Orléans, RMN 750MHz, CRMHT, Orléans, 2727Al 1D MAS Al 1D MAS
R=CaO/Al2O3=1
93%AlO4
Neuville et al. GCA, 2004, 68, 5071
CA 42_1468.9 (92.5)38.7 (7.6)
CA 42_1468.9 (92.5)38.7 (7.6)
CA42.14
CA 60_1063.4 (95.1)33.6 (4.9)
CA 60_1063.4 (95.1)
33.6 (4.9)
CA60.10CA33.17
CA 55_1864.7 (95.7)34.8 (4.3)
CA 55_1864.7 (95.7)
34.8 (4.3)
R=CaO/Al2O3=3
⇒1<R<3 92%AlIV and 8%Al V in glasses with classic (15°/s) and rapid quench (300°/s)
SiO2
CaO Al2O3Neuville et al. JNCS, 2007
Cax.yx=%SiO
2y=%Al 2O 3Mole%
SiO 2
Al 2 O 3CaO
Ca63.18
Ca50.25
Ca58.20
Ca70.15
Ca33.33
Ca29.36
Ca19.40
Ca76.11Ca77.07
Ca68.08
Ca60.10
Ca55.18
Ca50.12Ca50.00
Ca48.03
Ca44.11Ca46.07
Ca42.14
Ca39.22
Ca33.18
Ca32.17
Ca38.15Ca35.27
Ca23.21
Ca20.31
Ca12.44
Ca10.35
Ca16.21
Ca10.23
5050
50
Ca0.39C1
2A7=C
a0 . 36
CA2=C
a0.6
6
CA6=Ca0 . 86
Ca76.17
Ca50.30
Ca50.35
Ca33.43
Ca33.38
Ca10.50
Ca10.55
Ca50..40
Ca33.50
1<R<+3Al =>93% in AlIV
~7% in AlV
CA 0_2582.8 (100)
CA 0_2582.8 (100)
CA 16_2180.4 (100)
CA 16_2180.4 (100)
CA 10_2382.3 (100)
CA 0_3980.4 (100)
CA 0_3980.4 (100)
⇒Al 100% in AlIV
Al in Q2 and Q3 species
Peraluminous glassesAl in AlIV,AlV,AlVI
AlV,VI increasewith excess Al
Neuville et al. Chem Geol., 2006, 229, 173
800
900
1000
1100
1200
0 20 40 60 80 100
Mole % SiO2
Wav
en
um
ber
(cm
-1)
MAS
CAS
NAS
Neuville et al. Chem Geol., 2006, 229, 173
60
65
70
75
80
85
0 10 20 30 40 50 60 70 80
RM=1
RM=3
RC=1
RC=1.57
RC=3
!is
o [4
] Al
(pp
m)
Mole % SiO2
δiso [4]Al independant of MO/Al2O3and vary linearly with SiO2
CaO Al2O3 - Glass
27Al (ppm)20406080100
0
40
80
120
27Al (ppm)20406080100
17O
(ppm
)
δiso 74 ppmAl(µ2)3(µ3)
δiso 79 ppmAl(µ2)4
µ3
µ2
Consistent Consistent 1717O and O and 2727Al signature of Al signature of Al(µ2)3(µ3) structural entities
D.Iuga, C.Morais, Z.Gan, D.R.Neuville, L.Cormier, D.Massiot 'NMR Heteronuclear Correlation between Quadrupolar Nuclei in Solids.‘J. Am. Chem. Soc. 127 11540-11541 (2005)
Hetero-nuclear correlation
0
2
4
6
8
10
12
14
0 20 40 60 80 100
% [V
] Al
mole% SiO2
RC=1
RC=1.5
RC=3[VI]AlC
RM=3
RM
=1
[VI]AlM
Neuville et al. Chem Geol., 2006, 229, 173
1020
1040
1060
1080
1100
1120
1140
1160
1180
0 1 2 3 4 5
Tg
(K
)
Al2O3 / CaO
Peraluminous glasses
Perlimeglasses
Tec
tosi
lica
te j
oin
50% SiO2
76% SiO2
10% SiO2
33% SiO2
AlIV
AlV
AlV increases the viscosityAlV has a role of networkformer
0
10
20
30
40
50
60
0 2 4 6 8 10 12
% [5
] Al
Al2O3 /MO
33%SiO2
50%SiO2 CAS
Peraluminous glasses
10%SiO2
Tec
tosi
lica
te j
oin
// 8
AlV increases with Al2O3content for R=CaO/Al2O3<1
0
10
20
30
40
50
60
0 2 4 6 8 10 12
% [5
] Al
Al2O3 /MO
33%SiO2
50%SiO2 CAS
Peraluminous glasses
10%SiO2
Tec
tosi
lica
te j
oin
// 8
50%SiO2 MAS
0
10
20
30
40
50
60
0 2 4 6 8 10 12
% [5
] Al
Al2O3 /MO
33%SiO2
50%SiO2 CAS
Peraluminous glasses
10%SiO2
Tec
tosi
lica
te j
oin
// 8
50%SiO2 MAS
Al2SiO
5
Poe, McMillan et al..,
1992, 1994
SiO2
CaO Al2O3
CaO-Al2O3-SiO2 glasses: Al K-edge
Al in 4-fold coordination
SA32 SUPERACO- LURE
-1
0
1
2
3
4
5
6
7
1560 1570 1580 1590 1600 1610 1620 1630
no
rma
lize
d a
bso
rba
nce
E, eV
R = CaO/Al2O
3 = 3Al K-edge
A
B
C
D
Ca60.10
Ca42.14
Ca32.17
Ca23.21
Ca16.21
Ca10.23
C3A (Ca0.25)
Ca68.08
Al inQ2 species
Neuville et al. Chem. Geol., 2004, 213,153
Al K-edge
0
0.5
1
1.5
2
1540 1580 1620 1660 1700 1740 1780 1820
No
rma
liz
ed
In
ten
sity
E (eV)
1900K
1830K
300K
CaAl2Si
2O
8 T
l=1826K
1000Ka
cd
0.5
1
1.5
2
1560 1570 1580 1590
1900K1830K
300K 1000K
a
b c
AnorthiteCaAl2Si2O8
Crystal and melt 1000K => Al in 4 fold coordination
AlV
with increasing temperature few Al in 5 fold coordination appearaccording with NMR (Coté, 1993) and Raman spectroscopy (Daniel et al, 1995)
Al K-edge
0
0.4
0.8
1.2
1.6
2
2.4
1560 1580 1600 1620 1640 1660 1680 1700
No
rma
liz
ed
In
ten
sity
E (eV)
2050K
1950K
300K
CaAl2O
4
Tl=1878K
1500K
a
b
c d
800K
1750K
e
CA =CaAl2O4
Crystal and melt => Al in 4 fold coordination
AlV
with increasing temperature few Al in 5 fold coordination appearaccording with NMR (Couture et al, 1990)
Al K-edge
0
0.5
1
1.5
2
1540 1560 1580 1600 1620 1640 1660 1680 1700
No
rma
liz
ed
In
ten
sity
E (eV)
1950K
1830K
300K
Ca3Al
2O
6
Tl=1930K
1000K
a
b'
c de
C3A =Ca3Al2O6
Crystal => Al in 4 fold coordination with 2Bridging Oxygen, Q2 specieswith increasing temperature no changes areobserved
Neuville et al., 2007, Amer Mineral.
-2
0
2
4
6
8
10
12
14
4 5 6 7 8 9 10
CA0.50
CA0.19
Vis
cosit
y (lo
g Po)
104/T (K
-1)
Viscosity decrease with CaO, and Alevolves from Q4 to Q2 with CaO
CA
CAO.19
•With increase of SiO2 or Al2O3 : Q4
Al enters preferentialy in Q4 species⇒ the connectivity of the network is increases => higher viscosity⇒ high Tg
Ca-ConclusionsExplanations for the increase of Tg at low SiO2 content
•Glasses R=1 : Q4
few structural change - substitution Si/Al⇒ polymerization not change⇒ no Tg maximun⇒ [5]Al explain the Tg deviation
Q2
•High content in CaO : Al in Q2 low Tg
•Not need O tricluster to explain viscosity variation
Q4
1) MAS System
Richet et al.
2) CAS System
Richet et al.
3) CMAS System
1
3
5
7
9
11
13
15
5.25 6 6.75 7.5 8.25 9 9.75 10.5
Vis
cosi
té (
log p
ois
e)
104/T (K-1)
MgSiO3
CaSiO3
BB
(CaMg)SiO3
0
5
10
15
0 20 40 60 80 100V
iscosi
ty (
log p
ois
e)
1025 K
1050 K
mol % CaSiO3
1075 K
1225 K
1500 K
1750 K
Mixing Ca/MgV
isco
sity
(lo
g Po
)
960
1000
1040
1080
1120
0 20 40 60 80 100
100*Ca/(Ca+Mg)
Tg
(K
)
Anorthite glasses
Garnet glasses
Pyroxene glasses
Richet et al.
MgOCaO
0
5
10
15
0 20 40 60 80 100
Vis
cosit
y (
log p
ois
e)
1025 K
1050 K
mol % CaSiO3
1075 K
1225 K
1500 K
1750 K
log η = Ae + Be/TSconf (T)
with Cpconf = Cp
l - Cpg(Tg)
Sconf(T) = Sconf(Tg) +
Sconf(Tg) = Smix+ ΣxiSiconf (Tg)
Sconftop = ΣxiSiconf (Tg).
10
12
14
16
18
20
0 0.2 0.4 0.6 0.8 1
Sco
nf (J
/mol
K)
MgSiO3 CaSiO3mol % CaSiO3
Sconftop
Smix
Smix = - nR Xi ln XiXi=Ca/(Ca+Mg)
Ideal mixing => random distribution
Neuville and Richet, GCA, 1991
Richet et al.
MgOCaO
5
10
0 20 40 60 80 100
100*Ca/(Ca+Mg)
Sco
nf (J
/Mol
K)
Anorthite glasses
Garnet glasses
Pyroxene glasses
T=1100K
1unit formula
CMA50.25.6 CMA50.25.12 CMA50.25.18
(ppm)120 80 40 0
100
80
60
40
20
(ppm)120 80 40 0
100
80
60
40
20
(ppm)120 80 40 0
100
80
60
40
20
CMA50.25.00
(ppm)120 80 40 0
80
60
40
20
80 40 0
100
80
60
40
20
CMA50.25.25
100
(ppm)120
CMA42.14.00
120 80 40 0 (ppm)
100
80
60
40
20
CMA42.14.10
80 40 0 (ppm)
100
80
60
40
20
120
CMA42.14.21
(ppm)80 40 0
100
80
60
40
20
120
CMA42.14.32
80 40 0
100
80
60
40
20
(ppm)120
CMA42.14.42
60
80 40 0
100
80
40
20
(ppm)120
Anorthite glasses
Garnet glasses
MgO
CaO
Ca/Mg-Conclusions
•No significant changes in Raman spectroscopy
• viscosity measurements show a minimum at Tgwhich can be explain by an ideal mixing term in theconfigurational entropy
• the proportion of [5]Al increases with Al2O3
Conclusions•R=1 : substitution of Si by Al in Q4 species see by Raman,NMR are in good agreement with viscosity and configurationalentropy
• per-MO glasses: low amount of [5]Al and for the CAS system,Al in Q2 species for low SiO2 content.
• peraluminous glasses: [5]Al increases with Al2O3
• Tg increases with [5]Al => [5]Al can be a network former
• Ca/Mg mixing => [5]Al increases with Mg and viscosity can bepredict using an ideal mixing term
• No tricluster oxygen to explain properties variation in MAS,CAS, CMAS and probably also in NAS