Producing the Gradient Changes in Glass Refraction by the Ion Exchange Method — Selected Aspects

Rogoziński, R.

doi:10.5772/60641

Cited by 4 publications

(7 citation statements)

References 43 publications

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“…Absolute stress-optic coefficients were taken to be such that Eq (4) is fulfilled, hence C 1 ¼ À7:77 Â 10 À7 MPa -1 and C 2 ¼ À4:077 Â 10 À6 MPa -1 . For example, BK-7 glass has reported [52] to have C 1 ¼ À5:0 Â 10 À7 MPa -1 and C 2 ¼ À3:3 Â 10 À6 MPa -1 .…”

Section: Experimental Determination Of Stress-optic Coefficientmentioning

confidence: 97%

“…Considering the difficulties in the experimental determination of the constants C 1 and C 2 , we suggest calculating them using a simplified way: it was found from literature [34,52] that C 1 is *4 times smaller than C 2 . If assumed that such correlation is generally true, then we can calculate both absolute stress-optic coefficients by only knowing the experimentally measured C. By taking C 1 = constant, C 2 can be calculated from Eq (4) as C 2 ¼ C 1 À C. Some amount of error is introduced into calculation using such simplification.…”

Section: Experimental Determination Of Stress-optic Coefficientmentioning

confidence: 99%

“…Consequently, a residual stress profile develops in the glass [2][3][4][5][6][7][8][9][10][11]. Reviews on chemical strengthening of glass in general have been published by many authors [15,52,55,[61][62][63][64][65].…”

Section: Introductionmentioning

confidence: 99%

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Gradient scattered light method for non-destructive stress profile determination in chemically strengthened glass

et al. 2016

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A new non-destructive gradient scattered light method is presented for micronscale stress profile measurement in chemically strengthened (chemically tempered, ion exchanged) glass. Direct non-destructive stress measurement in the surface layer (\100 lm) of chemically strengthened glass is reported for the first time. This is accomplished by passing a narrow laser beam through the surface layer of the glass at a considerably large incidence angle of 81.9°. The theory of gradient scattered light method is based on the ray tracing of ordinary and extraordinary rays in chemically strengthened glass and calculating the optical retardation distribution along the curved ray path. The experimental approach relies on recording the scattered light intensity and calculating the optical retardation distribution from it. The stress profile is measured in a chemically strengthened (8 h at 480°C in a salt mixture of 80 mol% KNO 3 and 20 mol% NaNO 3 ) lithium aluminosilicate glass plate to illustrate the capability of the method. Measured surface compressive stress was -1053 MPa and case depth 365 lm. Method is validated with transmission photoelasticity. The method could also be used for stress profile measurement in all transparent flat materials (such as very thin thermally tempered glass slabs or polymers). Additional new applications could be: (1) enhanced version of Bradshaw's surface layer etching method for stress profile measurement in case of ultra-thin case depths \20 lm;(2) micron-scale non-destructive tomography of layered polymeric gradient-refractive-index materials. The experimental procedure is developed to the level of full automation and the measurement time is less than 10 s.

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Section: Experimental Determination Of Stress-optic Coefficientmentioning

confidence: 97%

Section: Experimental Determination Of Stress-optic Coefficientmentioning

confidence: 99%

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Gradient scattered light method for non-destructive stress profile determination in chemically strengthened glass

et al. 2016

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“…By increasing m, the shape of the simulated stress profile becomes more characteristic to chemically strengthened glass. In this simulation, d = 1.5 mm, m = 5 and

n_{prism} = 1.515

.To calculate the ray paths of the e‐ray and o‐ray, the absolute stress‐optic coefficients were taken to be

C_{1} = - 7.77 \times 10^{- 7}

MPa −1 and

C_{2} = - 4.077 \times 10^{- 6}

MPa −1 , which yields the stress‐optic coefficient C = 2.573 Brewster.…”

Section: Stress Equilibrium As a Function Of Known Surface Stress Andmentioning

confidence: 99%

Measurement of stress build‐up of ion exchange strengthened lithium aluminosilicate glass

Hödemann

Valdmann

Paemurru³

et al. 2019

J Am Ceram Soc

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A recently developed nondestructive method was used to investigate the stress buildup in chemically strengthened lithium aluminosilicate glass. We utilized an updated version of the gradient scattered light method, which now enables more precise determination of the depth coordinates, recovering a more detailed stress profile around the knee. The main motivation of the work was to characterize and optimize the development of the knee-shaped breaking point in stress profile in lithium aluminosilicate glass prepared by the Saunders-Kubichan method of one-step strengthening in a mixture of KNO 3 +NaNO 3 molten salt bath. In the industry, a two-step process is still commonly used to build such a stress profile; the one-step strengthening will simplify the process as well as save the cost. Compared to previous studies, which used a destructive method based on transmitted light photoelasticity, we found that in the samples ion exchanged for 24 hours, the knee-shaped breaking points were situated two times deeper whereas the case depths were 28% shallower. The measured stress profiles were validated by stress equilibrium and by comparison to Na + ion concentration profiles. K E Y W O R D S glass, ion exchange, polarization, refractive index, scattering 2408 | HÖDEMANN Et Al. How to cite this article: Hödemann S, Valdmann A, Paemurru M, et al. Measurement of stress build-up of ion exchange strengthened lithium aluminosilicate glass.

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“…They have the character of compressive stresses and reach the maximum value (in the order of hundreds of MPa) at the glass surface [8]. The stresses fade away at depths from a few to tens of µm (depending on the depth of the ion exchange area) [9,10]. The resulting stresses are examined using various methods [2].…”

Section: Introductionmentioning

confidence: 99%

Stresses Produced in the BK7 Glass by the K+–Na+ Ion Exchange: Real-Time Process Control Method

Rogoziński

2019

Applied Sciences

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The paper presents the results of tests on stresses produced by the K+↔Na+ ion exchange method in BK7 glass. Diffusion ion exchange processes were carried out in glass plates with a surface area of a few cm2. The duration of these processes ranged from several hours to several hundred hours; process temperatures from 370 to 402 degree Celsius were used. The area of the glass in which the ion exchange took place shows refractive changes which are also accompanied by stresses. The planar waveguides produced in this way were tested by optical methods (for wavelength = 677 nm) and the refractive index profiles for the Transverse Electric (TE)and Transverse Magnetic (TM) olarization states were determined. On the basis of elasto-optic constants, the resulting stresses were determined. The temperature characteristics of diffusion coefficients of exchanged ions were also determined. Based on them a numerical simulation of real-time diffusion processes was possible, which allowed to predict the stresses arising in the glass. A good agreement between these predictions and the results of measurements was obtained.

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Producing the Gradient Changes in Glass Refraction by the Ion Exchange Method — Selected Aspects

Cited by 4 publications

References 43 publications

Gradient scattered light method for non-destructive stress profile determination in chemically strengthened glass

Gradient scattered light method for non-destructive stress profile determination in chemically strengthened glass

Measurement of stress build‐up of ion exchange strengthened lithium aluminosilicate glass

Stresses Produced in the BK7 Glass by the K+–Na+ Ion Exchange: Real-Time Process Control Method

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