我是說跟DVD-RAM同屬相變化材料的DVD+/-RW

不然美國國家技術標準協會(NIST：National Institute of Standards and echnology)
所做的研究Care and Handling of CDs and DVDs
http://www.clir.org/pubs/reports/pub121/sec1.html

第4節
4. How Long Can You Store CDs and DVDs and Use Them Again?
http://www.clir.org/pubs/reports/pub121/sec4.html

4.3 CD-RW, DVD-RW, DVD+RW, DVD-RAM Discs
RW and RAM discs are generally not considered for long-term or archival use,
and life expectancy tests are seldom done for this medium. Rewritable discs use a phase-changing metal alloy film
for recording data and aluminum for the reflective layer. The alloy film is not as stable as the dye used in R discs
because the material normally degrades at a faster rate...

The phase-changing film is affected primarily by heat, but ultraviolet (UV) light may also be a factor in the aging process.
The combination of high temperature and UV light may further accelerate the aging process.
The combination of high temperatures and high relative humidity will also most likely accelerate the aging process,
just as it does with the organic dye used in R discs.

The data on the phase-changing metal alloy film layer can be erased and rewritten to a limited number of times
(about 1,000 times for RW discs and about 100,000 times for RAM discs).
This rewriting does, however, affect disc life expectancy; RW or RAM discs archived after the first recording
should have a longer life expectancy than those that have undergone several erase-recording cycles.
Given the normal degradation rate alone, the life expectancy for RW and RAM discs will be less than that of R discs.
Add to that multiple rewrites, and the life expectancy can be even less.

最後不就有提到
Given the normal degradation rate alone, the life expectancy for RW and RAM discs will be less than that of R discs.
Add to that multiple rewrites, and the life expectancy can be even less.

在OSTA(Optical Storage Technology Association)
Disc Longevity: How long will data recorded on writable DVD discs remain readable?
http://www.osta.org/technology/dvdqa/dvdqa11.htm

裡面有提到的Lifetime
DVD-RAM/DVD+/-RW：30年以上
DVD+/-R：100年