raman spectroscopy of silicate glasses and melts in geological...

Raman spectroscopyof silicate glasses and melts

in geological systemsStéphanie Rossano & Bjorn Mysen

Lava flow (Hawaï)

Melting of crystallinematerials

1100°C

≈ 30°C

Fast cooling (quench)to avoid

crystallization

Glass/melt science : the scientific issues

Geological interest Information on the Earth historyFormer historyMelt differentiationDynamic behaviourEarth evolution

Build / constrain / complete geochemical models

Stromboli (july 1999) Cré

dit p

hoto

@ S

. Ros

sano

Moldavite (15 Ma) Cré

dit p

hoto

@ S

. Ros

sano

viscosity, colouration,nucleation, … can bemodulated by a change :• in composition• in thermal treatment

Link composition / thermal historyto physico-chemical properties


Technological interest

Crédit photo @ S. Rossano


Cultural heritage interest

Understand alteration processesForesee glass durability

PhD J. Sterpenich (1998)

condensation

Meteoric water

Les-Noës-Près-Troyes (Aube)

Flow of asbestos« lava »

Flow of nuclear waste« lava »


Environmental interest

Slow coolingRapid cooling

Liquidstable

Glassout of equilibrium

Supercooledliquidmetastable

Crystalstable

mMelting temperatureGlass transition

temperature

Glass vs crystal ?

Glass vs crystal ?

Crystalline CaFeSi2O6Fe, Ca, Si, O

Glass of hedenbergitecompositionFe, Ca, O, Si

No periodicityNo more special atomic planes / directions

Increase of « disorder »

Qn species

Q4

Q2

QnTetrahedralentities centredon Si4+ or Al3+

Number of bridgingoxygens

Distribution of environments

Na2O-4SiO2 (classical MD)

Na, Si, O

Bridging O

Nonbridging O

Glass structure

Q2

Chargecompensationneeded for the

NBO

• competition betweencations• Distribution ofcationic environments

FeCaOSiNaAl

Tektite (Classical MD snapshot)

Complex compositions

FeCaOSiNaAl

Tektite (Classical MD snapshot)

Probing glass structureLocal order

Selective techniques 57Fe Mössbauer,

XAS,NMR…

Raman spectroscopy

• Species• Connectivity of the

glass network

1st order Raman spectrum +Al3+-O + P4+-O + Fe3+-O…

Qn

vibrationsVolatile vibrations CO2,CO, CH4, H2, H2O, N, S…

200 420028001300600

Alkaline earth - OAlkaline - OO - transition metal

800

Regions of interest

Network connectivity

Pre-treatment steps

Modified from Malfait & Halter (2008)

• Comparison between a seriesof spectra

• Extraction of quantitativeinformation

Pre-treatment steps

Baseline determination / substraction

• Spectrometer dependent

Modified from Malfait & Halter (2008) 200 400 600 800 1000 1200

K2O-MgO-2SiO

2

Raman shift, cm-1

• Spectrometer dependent• Fluorescence signal

Pre-treatment steps



• Spectrometer dependent• Fluorescence signal• Glass composition

Mercier et al. (2009)

Pre-treatment steps



Pre-treatment stepsT / ν correction

Modified from Malfait & Halter (2008) Hass, 1970

€

Icor = Imeasω

(ω0 −ω)4 (1− e

−hvω /kT )

Corrections necessary at high T or low frequency region

Pre-treatment steps

Daniel et al. 1995

CaAl2Si2O8 @2009 K

(1) Exp. spectrum

(2) Measured Thermalemission (laser off)

(1) - (2)

€

Icor = Imeasω

(ω0 −ω)4 (1− e

−hvω /kT )

Daniel et al. 1995

CaAl2Si2O8

Liq.

SupercooledLiq.

Glass

-

T

T0

Na2TiSi2O7

Reynard & Webb 1998

The Long formula does notcorrect for T dependence ofsd order Raman scattering

€

I (2) (ω) =Icorr (T )− Icorr (T0 )

n T − n T0

€

Icorr (T )− I(2) (ω)

€

Icorr (T )

€

I (2) (ω)

Daniel et al. 1995

Minimize misinterpretations

Changes observed are due toconfigurational changes oranharmonic effects

Pre-treatment stepsNormalization


Comparison of relativeintensities among spectra of asame family

• in a region with no Raman signal• to the most intense point• to the integrated Raman signal

Comparison between studiesdifficult

Tsujimura et al., 2004

Fingerprinting

Identification of Ramanbands due to dissolved

species

1st order Raman spectrum +Al3+-O + P4+-O + Fe3+-O…

Qn

vibrationsVolatile vibrations CO2,

CO, CH4, H2, H2O, N, S…

200 420028001300600

Alkaline earth - OAlkaline - O

O - transition metal

800

Isolated SO42- S6

2- Isolated SO42-

Quantification (external standard)

Lenoir et al., 2009

• Magmatic systems• industrial glasses : refining agent

Without refining agent2 Na2SO4 2Na2O + O2 + 2 SO2 With refining agent

Calibration lines are composition dependent

Sulfur At 1450°CA bubble of 0.1 mm140h = elevation of 1m

Lenoir et al., 2009

Application to melts

Fingerprinting

• Identification of pigments• Classification of samples

Tournié et al., 2011

Fingerprinting

Brawer & White (1977)

Comparison between glass and crystal

200

400

600

800

1000

0 200 400 600 800 1000 1200

verre CaMgSi2O6cristal CaMgSi2O6

cm-1

glass & crystal of CaMgSi2O6 composition

Statistical analysis

• Decomposition intoGaussian components• Least squares refinement• A posteriori assignment

Na2O-MgO-8SiO2

Modified from Trcera et al. (2011)

Polymerization

Na2O-MgO-xSiO2 with 2 < x < 10

Trcera et al. (2011)

Please : verify that theenvironment around atoms donot change

Trcera (personal com.)

1290 1300 1310 1320 1330 1340 1350

NMS2 norm.NMS3NMS4NMS6NMS8NMS10

Rel

ativ

e in

tens

ity

(arb

. uni

ts)

energy (eV)

Mg K-edge

Guide to interpret the trends Polymerization

Controversies : • Shape of the individual bands• Number of components• Assignments

Quantification of Qn species

29Si NMR spectroscopy

Not easy for meltsFrantz & Mysen (1995)

Statistical analysis

• Principal components analysis

• Linear combinations of partialspectra

• Optimization procedure

No need of external calibration melts

Necessity of a large number ofspectra in the same glass family

Number of independentcontributions

Internal standard for Qn

quantification

Statistical analysisExtraction of individual signals

assigned to Qn species

Malfait et al., JNCS 353 p4029 (2007) Zotov (1999)

Toplis & Reynard (2000)

melt dynamics0.9Na2O-0.1Al2O3-2SiO2+ 6mol% P2O5

Na3PO4 Na4P2O7

Reaction extent : A910-950/A800-1350

Phase separation

Conclusions and perspectives

• Raman has been extensivelyused to try to get insight intoglass connectivity

• Simple experiments

• Difficulty to analyze /interpret the spectra

GLASS MELT

Zotov, 1999 ; Spiekermann, 2012

• Quite easy to perform ascompared to other techniques(such as NMR for ex.)

• Access to the dynamics /kinetics of melt transformation

• Necessity to correct for sd

order Raman effect

Calculation could help to assign the peaks

raman spectroscopy of silicate glasses and melts in geological...

Documents