Safety glass — bullet-resistant glass is commonly made by laminating thick glass sheets with a core layer of which material? Choose the correct interlayer.

Introduction / Context:
Bullet-resistant glazing relies on energy absorption and dissipation through multiple layers. The design combines hard, brittle glass with tough, ductile polymer interlayers to arrest projectile motion and retain fragments. This question asks you to identify the typical interlayer material used between thick glass plies.

Given Data / Assumptions:

• Glass layers are relatively thick and arranged in multiple plies.
• Interlayer must be optically clear, tough, and adhesive.
• Civil/security applications (banks, vehicles, guard posts) are considered.

Concept / Approach:
Modern bullet-resistant glass is a laminated composite. Common constructions include alternating glass and polycarbonate or glass with PVB (polyvinyl butyral) and other high-performance plastics. The polymer layer absorbs energy, distributes stress, and prevents spall and hazardous shards. Metals like steel or chromium would destroy transparency and add weight, defeating the purpose of “glass.”

Step-by-Step Solution:

Verification / Alternative check:
Product standards for laminated safety and bullet-resistant glazing specify polymer interlayers (PVB, ionoplasts, polycarbonate) bonded to glass to achieve ballistic ratings.

Why Other Options Are Wrong:

• Steel/Stainless steel/Chromium: Opaque and incompatible with the optical requirements of glazing.

Common Pitfalls:
Confusing tempered glass (single ply, heat-treated) with laminated bullet-resistant constructions; assuming hardness alone stops bullets—toughness and energy absorption are crucial.

Final Answer:
High-test plastic (e.g., polycarbonate/PVB laminate)