ASTM C770 Glass Stress Optical Coefficient (SOC) Testing
ASTM C770 test method includes procedures for measuring the stress-optical coefficient of glass used in photoelastic analysis. The standard unit for the stress-optical coefficient is mm²/N.
TRUSTED BY
Precision-driven testing for dimensional accuracy and compliance
- Overview
- Scope, Applications, and Benefits
- Test Process
- Specifications
- Instrumentation
- Results and Deliverables
Overview
ASTM C770 determines the stress-optical coefficient of glass, which relates mechanical stress to optical birefringence. This property is essential for understanding how stress affects light transmission and optical performance in glass materials.
This method is widely used in optical glass, display technologies, and precision components. It helps evaluate stress-induced optical distortion and ensures material suitability for high-performance optical applications.
Scope, Applications, and Benefits
Scope
ASTM C770 evaluates the relationship between applied stress and resulting optical birefringence in glass. The test determines the stress-optical coefficient used for stress analysis and optical design.
The test evaluates:
- Stress-optical coefficient of glass
- Optical birefringence under stress
- Relationship between stress and optical behavior
- Internal stress effects on transparency
- Suitability for optical applications
Applications
- Optical and precision glass components
- Display panels and screens
- Fiber optics and photonics
- Scientific and laboratory glass
- Glass used in imaging systems
- Quality control in glass manufacturing
Benefits
- Provides accurate stress-optical property data
- Helps detect internal stress in glass
- Supports optical design and engineering
- Assists in improving product performance
- Enables comparison of glass materials
Test Process
Sample Preparation
Glass specimens are prepared with uniform thickness and smooth surfaces.
1Stress Application
Controlled mechanical stress is applied to the specimen.
2Optical Measurement
Birefringence is measured using polarized light techniques.
3Data Recording & Evaluation
Stress-optical coefficient is calculated from measured values.
4Technical Specifications
| Parameter | Details |
|---|---|
| Applicable Materials | Optical and structural glass |
| Specimen Thickness | ~1 mm to 10 mm |
| Stress Range | ~0.1 MPa to 50 MPa |
| Measurement Method | Polarized light analysis |
| Wavelength Range | ~400 nm to 700 nm |
| Measured Outputs | Stress-optical coefficient (Pa⁻¹ or Brewsters) |
Instrumentation Used for Testing
- Polariscope or photoelastic setup
- Light source (monochromatic or white light)
- Load application system
- Optical measurement system
- Sample preparation tools
- Data acquisition system
Results and Deliverables
- Stress-optical coefficient values
- Birefringence measurements
- Stress distribution analysis
- Optical performance evaluation
- Test condition summary
- ASTM compliance report
Frequently Asked Questions
Understanding the mechanical behavior of glass under stress is critical in applications requiring its optical and structural integrity, including safety glass or optical components.
The stress-optical coefficient is determined using Procedure A-fiber, Procedure B-rectangular beam, and Procedure C-glass disc methods. All involve the measurement of optical retardation under conditions of stress.
Procedure B tests the optical retardation of a rectangular glass beam in four-point bending, while procedure A uses a glass fiber in uniaxial tension. Procedure B gives a distribution of bending stress.
The stress-optical coefficient helps predict how the glass will respond to different stress conditions. This is particularly helpful in designing glass components in safety-critical applications such as structural glass and optical devices.
Fine annealing in Procedure B is crucial in eliminating any internal stresses in the glass beam, ensuring it responds predictably to bending forces, thus giving better measurements of the stress-optical coefficient.
Why Choose Infinita Lab
for Electron Energy Loss
Spectroscopy (EELS)?
At the core of this breadth is our network of 2,000+ accredited labs in the USA, offering access to over 10,000 test types. From advanced metrology (SEM, TEM, RBS, XPS) to mechanical, dielectric, environmental, and standardized ASTM/ISO testing, we give clients unmatched flexibility, specialization, and scale. You are not limited by geography, facility, or methodology – Infinita connects you to the right testing, every time.
Looking for a trusted partner for Electron Energy Loss Spectroscopy (EELS) Testing?
Send query us at hello@infinitlab.com or call us at (888) 878-3090 to learn more about our services and how we can support you.
Request a Quote
Submit your material details and receive testing procedures, pricing, and turnaround time within 24 hours.
Quick Turnaround and Hasslefree process
Confidentiality Guarantee
Free, No-obligation Consultation
100% Customer Satisfaction
