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